Light receiving member for use in electrophotography.

0001This invention relates to an improved light receiving member for use in electrophotography which is sensitive to electromagnetic waves such as light (which herein means in a broader sense those lights such as ultra-violet rays, visible rays, infrared rays, X-rays and y-rays).

0002For the photoconductive material to constitute a light receiving layer in a light receiving member for use in electrophotography, it is required to be highly sensitive, to have a high SN ratio [photocurrent (Ip)/dark current (Id)], to have absorption spectrum characteristics suited for the spectrum characteristics of an electromagnetic wave to be irradiated, to be quickly responsive and to have a desired dark resistance. It is also required to be not harmful to living things as well as man upon the use.

0003Especially, in the case where it is the light receiving member to be applied in an electrophotographic machine for use in office, causing no pollution is indeed important.

0004From these standpoints, the public attention has been focused on light receiving members comprising amorphous materials containing silicon atoms (hereinafter referred to as "a-Si"), for example, as disclosed in German Offenlegungsschriftes Nos. 2746967 and 2855718 which disclose use of the light receiving member as an image-forming member in electrophotography.

0005Other than these, Japanese Laid-open patent application 58-88753 discloses an amorphous silicon electrophotographic photoreceptor comprising a charge injection inhibition layer, a photoconductive layer and a surface protective layer, disposed in this order on a substrate, wherein the charge injection inhibition layer consists of n-type or p-type amorphous silicon; the photoconductive layer consists of amorphous silicon, amorphous silicon containing boron, amorphous silicon containing germanium or amorphous silicon containing boron and germanium; and the surface protective layer consists of amorphous silicon containing carbon. Further, Japanese Laid-open patent application 58-149053 discloses an amorphous silicon photoconductive member suitable for use in electrophotography which comprises an auxiliary layer, a charge injection inhibition layer, a first layer exhibiting photoconductivity and a second layer, disposed in this order on a substrate, wherein the auxiliary layer consists of amorphous material containing silicon atoms as the matrix, halogen atoms and nitrogen atoms; the charge injection inhibition layer consists of amorphous material containing silicon atoms as the matrix and atoms of an element belonging to Group V of the Periodic Table; the first layer consists of amorphous material containing silicon atoms as the matrix; and the second layer consists of amorphous material containing silicon atoms, carbon atoms and halogen atoms. Japanese Laid-open patent application 58-127934 discloses an amorphous silicon electrophotographic photoreceptor having a photoconductive layer of intrinsic amorphous silicon containing a trace amount of boron and current blocking p-n junction layers of doped microcrystalline silicon between the photoconductive layer and a conductive substrate. Japanese Laid-open patent application 58-163956 discloses an amorphous silicon electrophotographic photoreceptor having:

0006a conductive substrate;

0007first and second layers of amorphous silicon containing an element belonging to Group V of the Periodic Table, the first layer containing a graded concentration of oxygen;

0008an amorphous silicon photoconductive layer; and

0009an amorphous coating layer of silicon, carbon and a halogen.

0010For the conventional light receiving members comprising a-Si materials, there have been made improvements in their optical, electric and photoconductive characteristics such as dark resistance, photosensitivity, and photoresponsiveness, use-environmental characteristics, economic stability and durability.

0011However, there are still left subjects to make further improvements in their characteristics in the synthesis situation in order to make such light receiving member practically usable.

0012For example, in the case where such conventional light receiving member is employed in the light receiving member for use in electrophotography with aiming at heightening the photosensitivity and dark resistance, there are often observed a residual voltage on the conventional light receiving member upon the use, and when it is repeatedly used for a long period of time, fatigues due to the repeated use will be accumulated to cause the so-called ghost phenomena inviting residual images.

0013Further, in the preparation of the light receiving layer of the conventional light receiving member for use in electrophotography using an a-Si material, hydrogen atoms, halogen atoms such as fluorine atoms or chlorine atoms, elements for controlling the electrical conduction type such as boron atoms or phosphorus atoms, or other kinds of atoms for improving the characteristics are selectively incorporated in the light receiving layer.

0014However, the resulting light receiving layer sometimes becomes accompanied with defects on the electrical characteristics, photoconductive characteristics and/or breakdown voltage according to the way of the incorporation of said constituents to be employed.

0015That is, in the case of using the light receiving member having such light receiving layer, the life of a photocarrier generated in the layer with the irradiation of light is not sufficient, the inhibition of a charge injection from the side of the substrate in a dark layer region is not sufficiently carried out, and image defects likely due to a local breakdown phenomenon which is so-called "white oval marks on half-tone copies" or other image defects likely due to abrasion upon using a blade for the cleaning which is so-called "white line" are apt to appear on the transferred images on a paper sheet.

0016Further, in the case where the above light receiving member is used in a much moist atmosphere, or in the case where after being placed in that atmosphere it is used, the so-called "image flow" sometimes appears on the transferred images on a paper sheet.

0017In consequence, it is necessitated not only to make a further improvement in an a-Si material itself but also to establish such a light receiving member not to invite any of the foregoing problems.

0018In order to overcome the foregoing problems of the conventional light receiving member for use in electrophotography, the present inventors have made various studies while focusing on its surface layer and other constituent layer. As a result, the present inventors have found that when the surface layer is formed of an amorphous material containing silicon atoms, carbon atoms and hydrogen atoms and the content of the hydrogen atoms is controlled to be in the range between 41 and 70 atomic %, and that when at least one of other constituent layers except the surface layer is formed of a polycrystal material containing silicon atoms, those problems of the conventional light receiving member for use in electrophotography can be satisfactorily eliminated.

0019According to this invention there is provided a light receiving member for use in electrophotography comprising a substrate for electrophotography and a light receiving layer disposed on said substrate, the light receiving layer being constituted by a charge injection inhibition layer consisting of a polycrystal material containing silicon atoms as the main constituent atoms, at least one kind selected from hydrogen atoms and halogen atoms, and an element for controlling the conductivity which functions to prevent a charge from being injected from the side of the substrate, a photoconductive layer consisting of an amorphous material containing silicon atoms as the main constituent atoms and at least one kind selected from hydrogen atoms and halogen atoms, and a surface layer consisting of an amorphous material containing silicon atoms, carbon atoms and hydrogen atoms, the amount of the hydrogen atoms contained in the surface layer being in the range from 41 to 70 atomic %.

0020It is possible for the light receiving member to have an absorption layer for light of long wavelength (hereinafter referred to as "IR layer"), which is formed of an amorphous material or a polycrystal material containing silicon atoms and germanium atoms, and if necessary, at least either hydrogen atoms or halogen atoms [hereinafter referred to as "A-SiGe (H,X)" or "poly-SiGe (H,X)"], between the substrate and the charge injection inhibition layer.

0021It is also possible for the light receiving member to have a contact layer,which is formed of an amorphous material or a polycrystal material containing silicon atoms as the main constituent atoms and at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms [hereinafter referred to as "A-Si(N,O,C)" or "poly-Si(N,O,C)"], between the substrate and the IR layer or between the substrate and the charge injection inhibition layer.

0022And the above-mentioned photoconductive layer may contain one or more kinds selected from oxygen atoms, nitrogen atoms, and an element for controlling the conductivity as the layer constituent atoms.

0023The above-mentioned charge injection inhibition layer may contain hydrogen atoms and/or halogen atoms, and, further, in case where necessary, at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms as the layer constituent atoms.

0024The above-mentioned IR layer may contain one or more kinds selected from nitrogen atoms, oxygen atoms, carbon atoms, and an element for controlling the conductivity as the layer constituent atoms.

0025The light receiving member having the above-mentioned features is free from the foregoing problems of the conventional light receiving members for use in electrophotography, has a wealth of practically applicable excellent electric, optical and photoconductive characteristics and is accompanied with an excellent durability and satisfactory use environmental characteristics.

0026Particularly, this light receiving member has substantially stable electric characteristics without depending on the working circumstances, maintains a high photosensitivity and a high S/N ratio and does not invite any undesirable influence due to residual voltage even when it is repeatedly used for a long period of time. In addition, it has sufficient moisture resistance and optical fatigue resistance, and causes neither degradation upon repeating use nor any defect on breakdown voltage.

0027Because of this, this light receiving member, even upon repeated use for a long period of time, can be used to produce highly resolved visible images with clearer half tone, which images are highly dense, of good quality and stable. <ul id="ul0001" list-style="none"><li>Figure 1 (A) through Figure 1(D) are schematic views illustrating the typical layer constitution of a representative light receiving member for use in electrophotography according to this invention ;</li><li>Figure 2 through Figure 7 are views illustrating the thicknesswise distribution of germanium atoms in the IR layer;</li><li>Figure 8 through Figure 12 are views illustrating the thicknesswise distribution of the group III atoms or the group V atoms in the charge injection inhibition layer;</li><li>Figure 13 through Figure 19 are views illustrating the thicknesswise distribution of at least one kind selected from nitrogen atoms, oxygen atoms, and carbon atoms in the charge injection inhibition layer ;</li><li>Figure 20(A) through Figure 20(C) are schematic views for examples of the shape at the surface of the substrate in the light receiving member for use in electrophotography according to this invention ;</li><li>Figure 21 is a schematic view for a preferred example of the light receiving member for use in electrophotography according to this invention which has a light receiving layer as shown in Figure 1 (C) formed on the substrate having a preferred surface ;</li><li>Figures 22 through 23 are schematic explanatory views of a preferred method for preparing the substrate having the preferred surface used in the light receiving member shown in Figure 21 ;</li><li>Figure 24 is a schematic explanatory view of a fabrication apparatus for preparing the light receiving member for use in electrophotography according to this invention;</li><li>Figure 25 and Figure 26 are schematic views respectively illustrating the shape of the surface of the substrate in the light receiving member in Examples 9 and 23, and Examples 10 and 24;</li><li>Figure 27 is a view illustrating the thicknesswise distribution of boron atoms and oxygen atoms in the charge injection inhibition layer in Example 2; and</li><li>Figure 28 is a view illustrating the thicknesswise distribution of boron atoms and oxygen atoms in the charge injection inhibition layer and germanium atoms in IR layer in Example 12.</li></ul>

0028Representative embodiments of the light receiving member for use in electrophotography according to this invention will now be explained more specifically referring to the drawings. The description is not intended to limit the scope of this invention.

0029Representative light receiving members for use in electrophotography according to this invention are as shown in Figure 1 (A) through Figure 1(D), in which are shown light receiving layer 100, substrate 101, charge injection inhibition layer 102, photoconductive layer 103, surface layer 104, free surface 105, IR layer 106, and contact layer 107. <ul id="ul0002" list-style="none"><li>Figure 1 (A) is a schematic view illustrating a typical representative layer constituion of this invention, in which is shown the light receiving member comprising the substrate 101 and the light receiving layer 100 constituted by the charge injection inhibition layer 102, the photoconductive layer 103 and the surface layer 104.</li><li>Figure 1 (B) is a schematic view illustrating another representative layer constitution of this invention, in which is shown the light receiving member comprising the substrate 101 and the light receiving layer 100 constituted by the IR layer 106, the charge injection inhibition layer 102, the photoconductive layer 103 and the surface layer 104.</li><li>Figure 1 (C) is a schematic view illustrating another represntative layer constitution of this invention, in which is shown the light receiving member comprising the substrate 101 and the light receiving layer 100 constituted by the contact layer 107, the IR layer 106, the charge injection inhibition layer 102, the photoconductive layer 103 and the surface layer 104.</li><li>Figure 1 (D) is a schematic view illustrating another representative layer constitution of this invention, in which is shown the light receiving member comprising the substrate 101 and the light receiving layer constituted by the contact layer 107, the charge injection inhibition layer 102, the photoconductive layer 103 and the surface layer 104.</li></ul>

0030Now, explanation will be made for the substrate and each constituent layer in the light receiving member of this invention.

Substrate 101

0031The substrate 101 for use in this invention may either be electroconductive or insulative. The electroconductive support can include, for example, metals such as NiCr, stainless steels, Al, Cr, Mo, Au, Nb, Ta, V, Ti, Pt and Pb or the alloys thereof.

0032The electrically insulative support can include, for example, films or sheets of synthetic resins such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, and polyamide, glass, ceramic and paper. It is preferred that the electrically insulative substrate is applied with electroconductive treatment to at least one of the surfaces thereof and disposed with a light receiving layer on the thus treated surface.

0033In the case of glass, for instance, electroconductivity is applied by disposing, at the surface thereof, a thin film made of NiCr, Al, Cr, Mo, Au, lr, Nb, Ta, V, Ti, Pt, Pd, ln₂0₃, Sn0₂, ITO (in₂O₃ + Sn0₂), etc. In the case of the synthetic resin film such as a polyester film, the electroconductivity is provided to the surface by disposing a thin film of metal such as NiCr, Al, Ag, Pv, Zn, Ni, Au, Cr, Mo, lr, Nb, Ta, V, TI and Pt by means of vacuum deposition, electron beam vapor deposition, sputtering, etc., or applying lamination with the metal to the surface. The substrate may be of any configuration such as cylindrical, belt-like or plate-like shape, which can be properly determined depending on the application uses. For instance, in the case of using the light receiving member shown in Figure 1 in continuous high speed reproduction, it is desirably configurated into an endless belt or cylindrical form.

0034The thickness of the support member is properly determined so that the light receiving member as desired can be formed.

0035In the case where flexibility is required for the light receiving member, it can be made as thin as possible within a range capable of sufficiently providing the function as the substrate. However, the thickness is usually greater than 10 µm in view of the fabrication and handling or mechanical strength of the substrate.

0036And, it is possible for the surface of the substrate to be uneven in order to elimimate occurrence of defective images caused by a so-called interference fringe pattern being apt to appear in the formed images in the case where the image formation is carried out using coherent monochromatic light such as laser beams.

0037In that case, the uneven surface shape of the substrate can be formed by the grinding work with means of an appropriate cutting tool, for example, having a V-form bite.

0038That is, said cutting tool is firstly fixed to the predetermined position of milling machine or lathe, then, for example, a cylindrical substrate is moved regularly in the predetermined direction while being rotated in accordance with the predetermined program to thereby obtain a surface-treated cylindrical substrate of a surface having irregularities in reverse V-form with a desirably pitch and depth.

0039The irregularities thus formed at the surface of the cylindrical substrate form a helical structure along the center axis of the cylindrical substrate. The helical structure making the reverse V-form irregularities of the surface of the cylindrical substrate may be double or treble. Or otherwise, it may be of a cross-helical structure.

0040Further, the irregularities at the surface of the cylindrical substrate may be composed of said helical structure and a delay line formed along the center axis of the cylindrical substrate. The cross-sectional form of the convex of the irregularity formed at the substrate surface is in a reverse V-form in order to attain controlled unevenness of the layer thickness in the minute column for each layer to be formed and secure desired close bondability and electric contact between the substrate and the layer formed directly thereon.

0041And it is desirable for the reverse V-form to be an equilateral triangle, right-angled triangle or inequilateral triangle. Among these triangle forms, equilateral triangle form and right-angled triangle form are most preferred.

0042Each dimension of the irregularities to be formed at the substrate surface under the controlled conditions is properly determined having a due regard on the following points.

0043That is, firstly, a layer composed of, for example, a-Si(H,X) or poly-Si(H,X) to constitute a light receiving layer is structurally sensitive to the surface state of the layer to be formed and the layer quality is apt to largely change in accordance with the surface state.

0044Therefore, it is necessary for the dimention of the irregularity to be formed at the substrate surface to be determined not to invite any decrease in the layer quality.

0045Secondly, should there exist extreme irregularities on the free surface of the light receiving layer, cleaning in the cleaning process after the formation of visible images becomes difficult to sufficiently carry out. In addition, in the case of carrying out the cleaning with a blade, the blade will be soon damaged.

0046From the viewpoints of avoiding the problems in the layer formation and the electrophotographic processes, and from the conditions to prevent occurrence of the problems due to interference fringe patterns, the pitch of the irregularity to be formed at the substrate surface is preferably 0.3 to 500 µm, more preferably 1.0 to 200µm, and, most preferably, 5.0 to 50 µm.

0047As for the maximum depth of the irregularity, it is preferably 0.1 to 5.0 µm, more preferably 0.3 to 3.0 µm, and, most preferably, 0.6 to 2.0 µm.

0048And when the pitch and the depth of the irregularity lie respectively in the above-mentioned range, the inclination of the slope of the dent (or the linear convex) of the irregularity is preferably 1 to 200, more preferably 3 to 15 °, and, most preferably, 4 to 10 *.

0049Further, as for the maximum figure of a thickness difference based on the ununiformity in the layer thickness of each layer to be formed on such substrate surface, in the meaning within the same pitch, it is preferably 0.1 to 2.0 am, more preferably 0.1 to 1.5 am, and, most preferably, 0.2 µm to 1.0 am.

0050In alternative, the irregularity at the substrate surface may be composed of a plurality of fine spherical dimples which are more effective in eliminating the occurrence of defective images caused by the interference fringe patterns especially in the case of using coherent monochromatic light such as laser beams.

0051In that case, the scale of each of the irregularities composed of a plurality of fine spherical dimples is smaller than the resolving power required for the light receiving member for use in electrophotography.

0052A typical method of forming the irregularities composed of a plurality of fine spherical dimples at the substrate surface will be hereunder explained referring to Figures 22 and 23. <ul id="ul0003" list-style="none"><li>Figure 22 is a schematic view for a typical example of the shape at the surface of the substrate in the light receiving member for use in electrophotography according to this invention, in which a portion of the uneven shape is enlarged. In Figure 22, are shown a support 2201, a support surface 2202, a rigid true sphere 2203, and a spherical dimple 2204.</li><li>Figure 22 also shows an example of the preferred methods of preparing the surface shape as mentioned above. That is, the rigid true sphere 2203 is caused to fall gravitationally from a position at a predetermined height above the substrate surface 2202 and collide against the substrate surface 2202 to thereby form the spherical dimple 2204. A plurality of fine spherical dimples 2204 each substantially of an identical radius of curvature R and of an identical width D can be formed to the substrate surface 2202 by causing a plurality of rigid true spheres 2203 substantially of an identical diameter R' to fall from identical height h simultaneously or sequentially.</li><li>Figure 23 shows a typical embodiment of a substrate formed with the uneven shape composed of a plurality of spherical dimples at the surface as described above.</li></ul>

0053In the embodiment shown in Figure 23, a plurality of dimples pits 2304, 2304 ... substantially of an identical radius of curvature and substantially of an identical width are formed while being closely overlapped with each other thereby forming an uneven shape regularly by causing to fall a plurality of spheres 2303, 2303, ... regularly and substantially from an identical height to different positions at the surface 2302 of the support 2301. In this case, it is naturally required for forming the dimples 2304, 2304 ... overlapped with each other that the spheres 2303, 2303 ... are graviationally dropped such that the times of collision of the respective spheres 2303 to the support 2302 and displaced from each other.

0054By the way, the radius of curvature R and the width D of the uneven shape formed by the spherical dimples at the substrate surface of the light receiving member fur use in electrophotography according to this invention constitute an important factor for effectively attaining the advantageous effect of preventing occurrence of the interference fringe in the light receiving member for use in electrophotography according to this invention. The present inventors carried out various experiments and, as a result, found the following facts.

0055That is, if the radius of curvature R and the width D satisfy the following equation:<maths id="math0001" num=""><img file="EP0232145B1_D0001.tif" /></maths>0.5 or more Newton rings due to the sharing interference are present in each of the dimples. Further, if they satisfy the following equation:<maths id="math0002" num=""><img file="EP0232145B1_D0002.tif" /></maths>one or more Newton rings due to the sharing interference are present in each of the dimples.

0056From the foregoing, it is preferred that the ratio D/R is greater, than 0.035 and, preferably, greater than 0.055 for dispersing the interference fringes resulted throughout the light receiving member in each of the dimples thereby preventing occurrence of the interference fringe in the light receiving member.

0057Further, it is desired that the width D of the unevenness formed by the scraped dimple is about 500 µm at the maximum, preferably, less than 200 µm and, more preferably less than 100 /1.m.

0058Figure 21 is a schematic view illustrating a representative embodiment of the light receiving member in which is shown the light receiving member comprising the above-mentioned substrate 2101 and the light receiving layer 100 constituted by contact layer 2107, IR layer 2106, charge injection inhibition layer 2102, photoconductive layer 2103, and surface layer 2104 having free surface 2105.

0059<maths id="math0003" num=""><img file="EP0232145B1_D0003.tif" /></maths>

0060The contact layer 107 (or 2107) of this invention is formed of an amorphous material or a polycrystal material containing silicon atoms, at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms, and if necessary, hydrogen atoms or/and halogen atoms.

0061Further, the contact layer may contain an element for controlling conductivity.

0062The main object of disposing the contact layer in the light receiving member of this invention is to enhance the bondability between the substrate and the charge injection inhibition layer or between the substrate and the IR layer. And, when the element for controlling the conductivity is incorporated in the contact layer, the transportation of a charge between the substrate and the charge injection inhibition layer is effectively improved.

0063For incorporating various atoms in the contact layer, that is, at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms; elements for controlling the conductivity in case where necessary; they may be distributed either uniformly in the entire layer region or unevenly in the direction toward its layer thickness.

0064In the light receiving member of this invention, the amount of nitrogen atoms, oxygen atoms, or carbon atoms to be incorporated in the contact layer is properly determined according to use purposes.

0065It is preferably 5 x 10-⁴ to 7 x 10 atomic %, more preferably 1 x 10-³ to 5 x 10 atomic %, and, most preferably, 2 x 10-³ to 3 x 10 atomic %.

0066For the thickness of the contact layer, it is properly determined having a due regard to its bondability, charge transporting efficiency, and also to its producibility.

0067It is preferably 1 x 10-² to 1 x 10 /1.m, and, most preferably, 2 x 10-² to 5 /1.m.

0068As for the hydrogen atoms and halogen atoms to be optionally incorporated in the contact layer, the amount of hydrogen atoms or halogen atoms, or the sum of the amount of hydrogen atoms and the amount of halogen atoms in the contact layer is preferably 1 x 10-¹ to 7 x 10 atomic %. more preferably 5 x 10-¹ to 5 x 10 atomic %, and, most preferably, 1 to 3 x 10 atomic %.<maths id="math0004" num=""><img file="EP0232145B1_D0004.tif" /></maths>

0069In the light receiving member for use in electrophotography of this invention, the IR layer is formed of either A-SiGe(H,X) or poly-SiGe(H,X).

0070As for the germanium atoms to be contained in the IR layer, they may be distributed uniformly in its entire layer region or unevenly in the direction toward the layer thickness of its entire layer region.

0071However, in any case, it is necessary for the germanium atoms to be distributed uniformly in the direction parallel to the surface of the substrate in order to provide the uniformness of the characteristics to be brought out.

0072[Herein or hereinafter, the uniform distribution means that the distribution of germanium atoms in the layer is uniform both in the direction parallel to the surface of the substrate and in the thickness direction. The uneven distribution means that the distribution of germanium atoms in the layer is uniform in the direction parallel to the surface of the substrate but is uneven in the thickness direction.]

0073That is, in the case where the germanium atoms are contained unevenly in the direction toward the layer thickness of its entire layer region, the germanium atoms are incorporated so as to be in the state that these atoms are more largely distributed in the layer region near the substrate than in the layer apart from the substrate (namely in the layer region near the free surface of the light receiving layer) or in the state opposite to the above state.

0074In preferred embodiments, the germanium atoms are contained unevenly in the direction toward the layer thickness of the entire layer region of the IR layer.

0075In one of the preferred embodiments, the germanium atoms are contained in such state that the distributing concentration of these atoms is changed in the way of being decreased from the layer region near the substrate toward the layer region near the charge injection inhibition layer. In this case, the affinity between the IR layer and the charge injection inhibition becomes excellent. And, as later detailed, when the distributing concentration of the germanium atoms is made significantly large in the layer region adjacent to the substrate, the IR layer becomes to substantially and completely absorb the light of long wavelength that can be hardly absorbed by the photoconductive layer in the case of using a semiconductor laser as the light source. As a result, the occurrence of the interference caused by the light reflection from the surface of the substrate can be effectively prevented.

0076Explanation will be made to the typical embodiments of the distribution of germanium atoms to be contained unevenly in the direction toward the layer thickness of the IR layer while referring to Figures 2 through 7 showing the distribution of germanium atoms. However, this invention is no way limited only to these embodiments.

0077In Figures 2 through 7, the abscissa represent the distribution concentration C of germanium atoms and the ordinate represents the thickness of the IR layer; and t_B represents the extreme position of the IR layer containing germanium atoms is formed from the t_B side toward the t_T side.

0078Figure 2 shows the first typical example of the thickness-wise distribution of the germanium atoms in the IR layer. In this example, germanium atoms are distributed such that the concentration C remains constant at a value C₁ in the range from position t_B (at which the IR layer comes into contact with the substrate) to position t₁, and the concentration C gradually and continyously decreases from C₂ in the range from position ti to position t_T, where the concentration of the germanium atoms is C₃.

0079In the example shown in Figure 3, the distribution concentration C of the germanium atoms contained in the IR layer is such that concentration C₄ at position t_B continuously decreases to concentration C₅ at position t_T.

0080In the example shown in Figure 4, the distribution concentration C of the germanium atoms is such that the concentration C₆ remains constant in the range from position t_B and position t₂ and it gradually and continyously decreases in the range from position t₂ and position t_T. The concentration at position t_T is substantially zero. ("Substantially zero" means that the concentration is lower than the detectable limit.)

0081In the example shown in Figure 5, the distribution concentration C of the germanium atoms is such that concentration C₈ gradually and continuously decreases in the range from position t_B and position t_T, at which it is substantially zero.

0082In the example shown in Figure 6, the distribution concentration C of the germanium atoms is such that concentration C₉ remains constant in the range from position t_B to position t₃, and concentration C₉ linearly decreases to concentration C₁₀ o in the range from position t₃ to position t_T.

0083In the example shown in Figure 7, the distribution concentration C of the germanium atoms is such that concentration C₁₁ linearly decreases in the range from position t_B to position t_T, at which the concentration is substantially zero.

0084Several examples of the thicknesswise distribution of germanium atoms in the IR layer are illustrated in Figures 2 through 7. In the light receiving member of this invention, the concentration (C) of germanium atoms in the IR layer is preferred to be high at the position adjacent to the substrate and considerably low at the position adjacent to the interface t_T.

0085The thicknesswise distribution of germanium atoms contained in the IR layer is such that the maximum concentration C_max of germanium atoms is preferably greater than 1 x 10³ atomic ppm, more preferably greater than 5 x 10³ atomic ppm, and most preferably, greater than 1 x 10⁴ atomic ppm based on the total amount of silicon atoms and germanium atoms.

0086For the amount of germanium atoms to be contained in the IR layer, it is properly determined according to desired requirements. However, it is preferably 1 to 1 x 10⁶ atomic ppm, more preferably 10² to 9.5 x 10⁵ atomic ppm, and, most preferably, 5 x 10² to 8 x 10⁵ atomic ppm based on the total amount of silicon atoms and germanium atoms.

0087Further, the IR layer may contain at least one kind selected from the element for controlling the conductivity, nitrogen atoms, oxygen atoms and carbon atoms.

0088In that case, its amount is preferably 1 x 10-² to 4 x 10 atomic %, more preferably 5 x 10-² to 3 x 10 atomic %, and most preferably 1 x 10^-1 to 25 atomic %.

0089As for the element for controlling the conductivity, so-called impurities in the field of the semiconductor can be mentioned and those usable herein can include atoms belonging to the group III of the periodic table that provide p-type conductivity (hereinafter simply referred to as "group III atoms") or atoms belonging to the group V of the periodic table that provide n-type conductivity (hereinafter simply referred to as "group V atoms"). Specifically, the group III atoms can include B (boron), AI (aluminum), Ga (gallium), In (indium) and TI (thallium), B and Ga being particularly preferred. The group V atoms can include P (phosphorus), As (arsenic), Sb (antimony), and Bi (bismuth), P and Sb being particularly preferred.

0090For the amount of the element for controlling the conductivity, it is preferably 1 x 10-² to 5 x 10⁵ atomic ppm, more preferably 5 x 10^-1 to 1 x 10⁴ atomic ppm, and, most preferably, 1 to 5 x 10³ atomic ppm.

0091And as for the thickness of the IR layer, it is preferably 30 A (10Å = 1 nm) to 50 µm, more preferably 40 A to 40 µm, and, most preferably, 50 A to 30 µm.

Charge Injection inhibition Layer 102 (or 2102)

0092In the light receiving member for use in electrophotography of this invention, the charge injection inhibition layer is formed of poly-Si(H,X) containing the element for controlling the conductivity uniformly in the entire layer region or largely in the side of the substrate.

0093And said layer may contain at least one kind selected nitrogen atoms, oxygen atoms and carbon atoms in the state of being distributed uniformly in the entire layer region or partial layer region but largely in the side of the substrate.

0094Now, the charge injection inhibition layer can be disposed on the substrate, the IR layer, or the contact layer.

0095The halogen atom (X) to be contained in the charge injection inhibition layer include preferably F (fluorine), CI (chlorine), Br (bromine), and I (iodine), F and CI being particularly preferred.

0096The amount of hydrogen atoms (H), the amount of the hydrogen atoms (X) or the sum of the amounts for the hydrogen atoms and the halogen atoms (H+X) contained in the charge injection inhibition layer is preferably 1 to 40 atomic %, and, most preferably, 5 to 30 atomic %.

0097As for the element for controlling the conductivity to be contained in said layer, the group III or group V atoms can be used likewise in the case of the above-mentioned IR layer.

0098Explanation will be made to the typical embodiments for distributing the group III atoms or group V atoms in the direction toward the layer thickness in the charge injection inhibition layer while referring to Figures 8 through 12.

0099In Figures 8 through 12, the abscissa represents the distribution concentration C of the group III atoms or group V atoms and the ordinate represents the thickness of the charge injection inhibition layer; and t_B representsthe extreme position of the layer adjacent to the substrate and t_T represents the other extreme position of the layer which is away from the substrate.

0100The charge injection inhibition layer is formed from the t_B side toward the t_T side.

0101Figure 8 shows the first typical example of the thicknesswise distribution of the group III atoms or group V atoms in the charge injection inhibition layer. In this example, the group III atoms or group V atoms are distributed such that the concentration C remains constant at a value C_{12 2}in the range from position t_B to position t₄, and the concentration C gradually and continuously decreases from C₁₃ in the range from position t₄ to position t_T, where the concentration of the group III atoms or group V atoms is C₁₄.

0102In the example shown in Figure 9, the distribution concentration C of the group III atoms or group V atoms contained in the light receiving layer is such that concentration C₁₅ at position t_B continuously decreases to concentration C₁₆ at position t_T.

0103In the example shown in Figure 10, the distribution concentration C of the group III atoms or group V atoms is such that concentration C₁₇ remains constant in the range from position t_B to position t₃, and concentration C₁₇ linearly decreases to concentration C₁₈ in the range from position t₅ to position t_T.

0104In the example shown in Figure 11, the distribution concentration C of the group III atoms or group V atoms is such that concentration C₁₉ remains constant in the range from position t_B and position t₆ and it linearly decreases from C₂₀ to C₂₁ in the range from position t₆ to position t_T.

0105In the example shown in Figure 12, the distribution concentration C of the group III atoms or group V atoms is such that concentration C₂₂ remains constant in the range from position t_b and position t_T.

0106In the case where the group III atoms or group V atoms are contained in the charge injection inhibition layer in such way that the distribution concentration of the atoms in the direction of the layer thickness is higher in the layer region near the substrate, the thicknesswise distribution of the group III atoms or group V atoms is preferred to be made inthe way that the maximum concentration of the group III atoms or group V atoms is controlled to be preferably greater than 50 atomic ppm, more preferably greater than 80 atomic ppm, and, most preferably, greater than 10² atomic ppm.

0107For the amount of the group III atoms or group V atoms to be contained in the charge injection inhibition layer, it is properly determined according to desired requirements. However, it is preferably 3 x 10 to 5 x 10⁵ atomic ppm, more preferably 5 x 10 to 1 x 10⁴ atomic ppm, and, most preferably, 1 x 10² to 5 x 10³ atomic ppm.

0108When at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms is incorporated in the charge injection inhibition layer, not only the mutual contact between the IR layer and the charge injection inhibition layer and the bondability between the charge injection inhibition layer and the photoconductive layer but also the adjustment of band gap for that layer are effectively improved.

0109Explanation will be made to the typical embodiments for distributing at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms in the direction toward the layer thickness in the charge injection inhibition layer, with reference to Figures 13 through 19.

0110In Figures 13 through 19, the abscissa represents the distribution concentration C of at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms, and the ordinate represents the thickness of the charge injection inhibition layer; and t_B represents the extreme position of the layer adjacent to the substrate and t_T represents the other extreme position of the layer which is away from the substrate. The charge injection inhibition layer is formed from the t_B side toward the t_T side.

0111Figure 13 shows the first typical example of the thicknesswise distribution of at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms in the charge injection inhibition layer. In this example, at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms are distributed such that the concentration C remains constant at a value C₂₃ in the range from position t_B to position t₇, and the concentration C gradually and continyously decreases from C₂₄ in the range from position t₇ to position t_T, where the concentration of at least one kind selected from nitrogen atoms, oxygen atoms, and carbon atoms is C_2S.

0112In the example shown in Figure 14, the distribution concentration C of at least one kind selected from nitrogen atoms, oxygen atoms, and carbon atoms contained in the charge injection inhibition layer is such that concentration C₂₆ at position t_B continuously decreases to concentration C₂₇ at position t_T.

0113In the example shown in Figure 15, the distribution concentration C of at least one kind selected from nitrogen atoms, oxygen atoms, and carbon atoms is such that concentration C₂₈ remains constant in the range from position t_B and position t₈ and it gradually and continyously decreases from position t₈ and becomes substantially zero between t₈ and t_T.

0114In the example shown in Figure 16, the distribution concentration C of at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms is such that concentration C₃₀ gradually and continyously decreases from position t_B and becomes substantially zero between t_B and t_T.

0115In the example shown in Figure 17, the distribution concentration C of at least one kind selected from nitrogen atims, oxygen atoms and carbon atoms is such that concentration C₃₁ remains constant in the range from position t_B to position t₃, and concentration Cs linearly decreases to concentration C₃₂ in the range from position t₉ to position t_T.

0116In the example shown in Figure 18, the distribution concentration C of at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms is such that concentration C₃₃ remains constant in the range from position t_B and position t₁₀ and it linearly decreases from C₃₄ to C₃₅ in the range from position t₁₀ o to position t_T.

0117In the example shown in Figure 19, the distribution concentration C of at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms is such that concentration C₃₆ remains constant in the range from position t_B and position t_T.

0118In the case where at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms is contained in the charge injection inhibition layer such that the distribution concentration of these atoms in the layer is higher in the layer region near the substrate, the thicknesswise distribution of at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms is made in such way that the maximum concentration of at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms is controlled to be preferably greater than 5 x 10² atomic ppm, more preferably, greater than 8 x 10² atomic ppm, and, most preferably, greater than 1 x 10³ atomic ppm.

0119As for the amount of at least one kind selected from nitrogen atoms, oxygen atoms and carbon atoms is properly determined according to desired requirements. However, it is preferably 1 x 10-³ to 50 atomic %, more preferably, 2 x 10-³ atomic % to 40 atomic %, and, most preferably, 3 x 10-³ to 30 atomic %.

0120For the thickness of the charge injection inhibition layer, it is preferably 1 x 10-² to 10 µm, more preferably, 5 x 10-² to 8 µm, and, most preferably, 1 x 10^-1 to 5 µm in the viewpoints of bringing about electrophotographic characteristics and economical effects.

Photoconductive Layer 103 (or 2103)

0121The photoconductive layer 103 (or 2103) is disposed on the substrate 101 (or 2102) as shown in Figure 1 (or Figure 21).

0122The photoconductive layer is formed of an A-Si(H,X) material or an A-Si(H,X)(O,N) material.

0123The photoconductive layer has the semiconductor characteristics as under mentioned and shows a photoconductivity against irradiated light. <ul id="ul0004" list-style="none"><li>(i) p-type semiconductor characteristics : containing an acceptor only or both the acceptor and a donor in which the relative content of the acceptor is higher;</li><li>(ii) p-type semiconductor characteristics : the content of the acceptor (Na) is lower or the relative content of the acceptor is lower in the case (i);</li><li>(iii)n-type semiconductor characteristics : containing a donor only or both the donor and an acceptor in which the relative content of the donor is higher;</li><li>(iv) n-type semiconductor characteristics : the content of donor (Nd) is lower or the relative content of the acceptor is lower in the case (iii); and</li><li>(v) i-type semiconductor characteristics :</li></ul><ul id="ul0005" list-style="none"><li>Na=_Nd=0 or Na=_Nd.</li></ul>

0124In order for the photoconductive layer to be a desirable type selected from the above-mentioned types (i) to (v), it can be carried out by doping a p-type impurity, an n-type impurity or both the impurity with the photoconductive layer to be formed during its forming process while controlling the amount of such impurity.

0125As the element to be such impurity to be contained in the photoconductive layer, the so-called impurities in the field of the semiconductor can be mentioned, and those usable herein can include atoms belonging to the group III or the periodical table that provide p-type conductivity (hereinafter simply referred to as "group III atom") or atoms belonging to the group V of the periodical table that provide n-type conductivity (hereinafter simply referred to as "group V atom"). Specifically, the group III atoms can include B (boron), AI (aluminum), Ga (gallium), In (indium) and TI (thallium). The group V atoms can include, for example, P (phosphor), As (arsenic), Sb (antimony) and Bi (bismuth). Among these elements, B, Ga, P and As are particularly preferred.

0126The amount of the group III atoms or the group V atoms to be contained in the photoconductive layer is preferably 1 x 10-³ to 3 x 10² atomic ppm, more preferably, 5 x 10-³ to 1 x 10² atomic ppm, and, most preferably, 1 x 10-² to 50 atomic ppm.

0127In the photoconductive layer, oxygen atoms or/and nitrogen atoms can be incorporated in the range as long as the characteristics required for that layer is not hindered.

0128In the case of incorporating oxygen atoms or/and nitrogen atoms in the entire layer region of the photoconductive layer, its dark resistance and close bondability with the substrate are improved.

0129The amount of oxygen atoms or/and nitrogen atoms to be incorporated in the photoconductive layer is desired to be relatively small not to deteriorate its photoconductivity.

0130In the case of incorporating nitrogen atoms in the photoconductive layer, its photosensitivity in addition to the above advantages may be improved when nitrogen atoms are contained together with boron atoms therein.

0131The amount of one kind selected from nitrogen atoms (N), and oxygen atoms (O) or the sum of the amounts for two kinds of these atoms to be contained in the photoconductive layer is preferably 5 x 10-⁴ to 30 atomic %, more preferably, 1 x 10-² to 20 atomic %, and, most preferably, 2 x 10-² to 15 atomic %.

0132The amount of the hydrogen atoms (H), the amount of the halogen atoms (H) or the sum of the amounts for the hydrogen atoms and the halogen atoms (H + X) to be incorporated in the photoconductive layer is preferably 1 to 40 atomic %, more preferably, 5 to 30 atomic %.

0133The halogen atom (X) includes, specifically, fluorine, chlorine, bromine and iodine. And among these halogen atoms, fluorine and chlorine and particu-larly preferred.

0134The thickness of the photoconductive layer is an important factor in order for the photocarriers generated by the irradiation of light having desired spectrum characteristics to be effectively transported, and it is appropriately determined depending upon the desired purpose.

0135It is, however, also necessary that the layer thickness be determined in view of relative and organic relationships in accordance with the amounts of the halogen atoms and hydrogen atoms contained in the layer or the characteristics required in the relationship with the thickness of other layer. Further, it should be determined also in economical viewpoints such as productivity or mass productivity. In view of the above, the thickness of the photoconductive layer is preferably 1 to 100 am, more preferably, 1 to 80 am, and, most preferably, 2 to 50 I.Lm.

Surface Layer 104 (or 2104)

0136The surface layer 104 (or 2104) having the free surface 105 (or 2105) is disposed on the photoconductive layer 103 (or 2103) to attain the objects chiefly of moisture resistance, deterioration resistance upon repeating use, electrical voltage withstanding property, use environmental characteristics and durability for the light receiving member for use in electrophotography according to this invention.

0137The surface layer is formed of the amorphous material containing silicon atoms as the constituent element which are also contained in the layer constituent amorphous material for the photoconductive layer, so that the chemical stability at the interface between the two layers is sufficiently secured.

0138Typically the surface layer is formed of an amorphous material containing silicon atoms, carbon atoms, and hydrogen atoms (hereinafter referred to as "A-(Si_xC_1-x)_yH_1-y", x>0 and y<1).

0139It is necessary for the surface layer for the light receiving member for use in electrophotography according to this invention to be carefully formed in order for that layer to bring about the characteristics as required.

0140That is, a material containing silicon atoms (Si), carbon atoms (C) and hydrogen atoms (H) as the constituent elements is structually extended from a cyrstalline state to an amorphous state which exhibit electrophysically properties from conductiveness to semiconductiveness and insulativeness, and other properties from photoconductiveness to in photoconductiveness according to the kind of a material.

0141Therefore, in the formation of the surface layer, appropriate layer forming conditions are required to be strictly chosen under which a desired surface layer composed of A-Sixci-x having the characteristics as required may be effectively formed.

0142For instance, in the case of disposing the surface layer with aiming chiefly at improvements in its electrical voltage withstanding property, the surface layer composed of A-(Si_xC_i-y)y : H₁-y is so formed that it exhibits a significant electrical insulative behavior in use environment.

0143In the case of disposing the surface layer with aiming at improvements in repeating use characteristics and use environmental characteristics, the surface layer composed of A-Si_xc_i-_x is so formed that it has certain sensitivity to irradiated light although the electrical insulative property should be somewhat decreased.

0144The amount of carbon atoms and the amount of hydrogen atoms respectively to be contained in the surface layer of the -ight receiving member for use is electrophotography according to this invention are important factors as well as the surface layer forming conditions in order to make the surface layer accompanied with desired characteristics to attain the objects of this invention.

0145The amount of the carbon atoms (C) to be incorporated in the surface layer is preferably 1 x 10-³ to 90 atomic %, and, most preferably, 10 to 80 atomic % respectively to the sum of the amount of the silicon atoms and the amount of the carbon atoms.

0146The amount of the hydrogen atoms to be incorporated in the surface layer is preferably 41 to 70 atomic %, more preferably 41 to 65 atomic %, and, most preferably, 45 to 60 atomic % respectively to the sum of the amount of all the constituent atoms to be incorporated in the surface layer.

0147As long as the amount of the hydrogen atoms to be incorporated in the surface layer lies in the above-mentioned range, any of the resulting light receiving members for use in electrophotography becomes wealthy in significantly practically applicable characteristics and to excel the conventional light receiving members for use in electrophotography in every viewpoint.

0148That is, for the conventional light receiving member for use in electrophotography, that is known that when there exist certain defects within the surface layer composed of A-(Si_xC_1-x)_y : H₁-y (due to mainly dangling bonds of silicon atoms and those of carbon atoms) they give undesiable influences to the electrophotographic characteristics.

0149For instance, becasue os such defects there are often invited deterioration in the electrification characteristics due to charge injection from the side of the free surface, changes in the electrification characteristics due to alterations in the surface structure under certain use environment, for example, high moisture atmosphere, and appearance of residual images upon repeating use due to that an electric charge is injected into the surface layer from the photoconductive layer at the time of corona discharge or at the time of light irradiation to thereby make the electric charge trapped for the defects within the surface layer.

0150However, the above defects being present in the surface layer of the conventional light receiving member for use in electrophotography which invite various problems as mentioned above can be largely eliminated by controlling the amount of the hydrogen atoms to be incorporated in the surface layer to be more than 41 atomic %, and as a result, the foregoing problems can be almost resolved. In addition, the resulting light receiving member for use in electrophotography becomes to have extremely improved advantages especially in the electric characteristics and the repeating usability at high speed in comparison with the conventional light receiving member for use in electrophotography.

0151And, the maximum amount of the hydrogen atoms to be incorporated in the surface layer is necessary to be 70 atomic %. That is, when the amount of the hydrogen atoms exceeds 70 atomic %, the hardness of the surface layer is undesirably decreased so that the resulting light receiving member becomes such that can not be repeatedly used for along period of time.

0152In this connection, it is an essential factor for the light receiving member for use in electrophotography of this invention that the surface layer contains the amount of the hydrogen atoms ranging in the above- mentione range.

0153For the incorporation of the hydrogen atoms in said particular amount in the surface layer, it can be carried out by appropriately controlling the related conditions such as the flow rate of a starting gaseous substance, the temperature of a substrate, discharging power and the gas pressure.

0154Specifically, in the case where the surface layer is formed of A-(Si_xC_1-x)_y : H₁-y, the "x" is preferably 0.1 to 0.99999, more preferably 0.1 to 0.99, and, most preferably, 0.15 to 0.9. And the "y" is preferably 0.3 to 0.59, more preferably 0.35 to 0.59, and, most preferably, 0.4 to 0.55.

0155The thickness of the surface layer in the light receiving member according to this invention is appropriately determined depending upon the desired purpose.

0156It is, however, also necessary that the layer thickness be determined in view of relative and organic relationships in accordance with the amounts of the halongen atoms, hydrogen atoms and other kind atoms contained in the layer or the characteristics required in the relationship with the thickness of other layer. Further, it should be determined also in economical point of view such as productivity or mass productivity. In view of the above factors, the thickness of the surface layer is preferably 0.003 to 30 am, more preferably, 0.004 to 20 am, and, most preferably, 0.005 to 10 µm.

0157By the way, the thickness of the light receiving layer 100 constituted by the photoconductive layer 103 (or 2103 in Figure 21) and the surface layer 104 (or 2104 in Figure 21) in the light receiving member for use in electrophotography according to this invention is appropriately determined depending upon the desired purpose.

0158In any case, said thickness is appropriately determined in view of relative and organic relationships between the thickness of the photoconductive layer and that of the surface layer so that the various desired characteristics for each of the photoconductive layer and the surface layer in the light receiving member for use in electrophotography can be sufficiently brought about upon the use to effectively attain the foregoing objects of this invention.

0159And, it is preferred that the thicknesses of the photoconductive layer and the surface layer be determined so that the ratio of the former versus the latter lies in the range of some hundred times to some thousand times.

0160Specifically, the thickness of the light receiving layer 100 is preferably 3 to 100 am, more preferably 5 to 70 am, and, most preferably, 5 to 50 µm.

Preparation of Layers

0161The method of forming the light receiving layer 100 of the light receiving member will be now explained.

0162Each of the layers to constitute the light receiving layer of the light receiving member of this invention is properly prepared by vacuum deposition method utilizing the discharge phenomena such as glow discharging, sputtering and ion plating methods wherein relevant gaseous starting materials are selectively used.

0163These production methods are properly used selectively depending on the factors such as the manufacturing conditions, the installation cost required, production scale and properties required for the light receiving members to be prepared. The glow discharging method or sputtering method is suitable since the control for the condition upon preparing the light receiving members having desired properties are relatively easy, and hydrogen atoms, halogen atoms and other atoms can be introduced easily together with silicon atoms. The glow discharging method and the sputtering method may be used together in one identical system.

Preparation of Contact Layer, IR Layer, Charge Injection Inhibition Layer, and Photoconductive Layer

0164Basically, when the charge injection inhibition layer constituted with poly-Si(H,X) or/and the photoconductive layer constituted with A-Si(H,X) are formed, for example, by the glow discharging process, gaseous starting material capable of supplying silicon atoms (Si) are introduced together with gaseous starting material for introducing hydrogen atoms (H) and/or halogen atoms (X) into a deposition chamber the inside pressure of which can be reduced, glow discharge is generated in the deposition chamber, and a layer composed of A-Si(H,X) or/and poly-Si(H,X) are formed on the surface of a substrate placed in a deposition chamber.

0165In the case of forming such layers by the reactive sputtering process, they are formed by using a Si target and by introducing a gas or gases material capable of supplying halogen atoms (X) or/and hydrogen atoms (H), if necessary, together with an inert gas such as He or Ar into a sputtering deposition chamber to thereby form a plasma atmosphere and then sputtering the Si target.

0166In the case of forming the IR layer constituted with A-SiGe(H,X) or poly-SiGe(H,X) by the glow discharging process, gaseous starting material capable of supplying silicon atoms (Si) is introduced together with gaseous starting material capable of supplying germanium atoms (Ge), and if necessary gaseous starting material for introducing hydrogen atoms (H) and/or halogen atoms (X) into a deposition chamber the inside pressure of which can be reduced, glow discharge is generated in the deposition chamber, and a composed of A-SiGe(H,X) or poly-Si(H,X) is formed on the surface of the substrate placed in the deposition chamber.

0167To form the IR layer of A-SiGe(H,X) or poly-SiGe(H,X) by the reactive sputtering process, a single target composed of silicon, or two targets (the said target and a target composed of germanium), further a single target composed of silicon and germanium is subjected to sputtering in atmosphere of an inert gas such as He or Ar, and if necessary gaseous starting material capable of supplying germanium atoms diluted with an inert gas such as He or Ar and/or gaseous starting material for introducing hydrogen atoms (H) and/or halogen atoms (X) are introduced into the sputtering deposition chamber thereby forming a plasma atmosphere with the gas.

0168The gaseous starting material for supplying Si can include gaseous or gasifiable silicon hydrides (silanes) such as SiH₄, Si₂H₆, Si₃H₈, Si₄H₁₀, etc., SiH₄ and Si₂H₆ being particularly preferred in view of the easy layer forming work and the good efficiency for the supply of Si.

0169The gaseous starting material for supplying Ge can include gaseous or gasifiable germanium hydrides such as GeH₄, Ge₂H₆, Ge₃H₈, Ge₄H₁₀, Ge₅H₁₂, Ge₆H₁₄, Ge₇H₁₆, Ge₈H₁₈, and Ge₉H₂₀, etc., GeH₄, Ge₂H₆, and Ge₃H₈ being particularly preferred in view of the easy layer forming work and the good efficiency for the supply of Ge.

0170Further, various halogen compounds can be mentioned as the gaseous starting material for introducing the halogen atoms and gaseous or gasifiable halogen compounds, for example, gaseous halogen, halides, inter-halogen compounds and halogen-substituted silane derivatives are preferred. Specifically, they can include halogen gas such as of fluorine, chlorine, bromine, and iodine; inter-halogen compounds such as BrF, CIF, CIF₃, BrF₂, BrF₃, IF₇, ICI, lBr, etc.; and silicon halides such as SiF₄, Si₂F₆, SiCl₄, and SiBr₄.

0171The use of the gaseous or gasifiable silicon halides as described above for forming a light receiving layer composed of poly-Si or A-Si containing halogen atoms as the constituent atoms by the glow discharging process is particularly advantageous since such layer can be formed with no additional use of gaseous starting material for supplying Si such as silicon hydride.

0172And, basically, in the case of forming a light receiving layer containing halogen atoms by the glow discharging process, for example, a mixture of a gaseous silicon halide substance as the starting material for supplying Si and a gas such as Ar, H₂ and He is introduced into the deposition chamber having a substrate in a predetermined mixing ratio and at a predetermined gas flow rate, and the thus introduced gases are exposed to the action of glow discharge to thereby cause a plasma resulting in forming said layer on the substrate. And, for incorporating hydrogen atoms in said layer, an appropriate gaseous starting material for supplying hydrogen atoms can be additionally used.

0173In the case of forming the IR layer, the above-mentioned halides or halogen-containing silicon compounds can be used as the effective gaseous starting material for supplying halogen atoms. Other examples of the starting material for supplying halogen atoms can include germanium hydride halides such as GeHF₃, GeH₂F₂, GeH₃F, GeHCl₃, GeH₂CI₂, GeH₃Cl, GeHBr₃, GeH₂Br₂, GeH₃Br, GeHI₃, GeH₂1₂, and GeH₃1; and germanium halides such as GeF₄, GeCl₄, GeBr₄, GeI₄, GeF₂, GeCI₂, GeBr₂, and Gel₂. They are in the gaseous form or gasifiable substances.

0174And in any case, one of these gaseous or gasifiable starting materials or a mixture of two or more of them in a predetermined mixing ratio can be selectively used.

0175As above mentioned, in the case of forming a layer composed constituted with, for example, poly-Si-(H,X) or A-Si(H,X) by the reactive sputtering process, such layer is formed on the substrate by using an Si target and sputtering the Si target in a plasma atmosphere.

0176And, in order to form such layer by the ion-plating process, the vapor of polycrystal silicon or single crystal silicon is allowed to pass through a desired gas plasma atmosphere. The silicon vapor is produced by heating the polycrystal silicon or single crystal silicon held in a boat. The heating is accomplished by resistance heating or in accordance with the electron beam method (E.B. method).

0177In either case where the sputtering process or the ion-plating process is employed, the layer may be incorporated with halogen atoms by introducing one of the above-mentioned gaseous halides or halogen-containing silicon compounds into the deposition chamber in which a plasma atmosphere of the gas is produced. In the case where the layer is incorporated with hydrogen atoms in accordance with the sputtering process, a feed gas to liberate hydrogen is introduced into the deposition chamber in which a plasma atmosphere of the gas is produced. The feed gas to liberate hydrogen atoms includes H₂ gas and the above-mentioned silanes.

0178As for the gaseous or gasifiable starting material for incorporating halogen atoms in the IR layer, charge injection inhibition layer or photoconductive layer, the foregoing halide, halogen-containing silicon compound or halogen-containing germanium compound can be effectively used. Other effective examples of said material can include hydrogen halides such as HF, HCI, HBr and HI and halogen-substituted silanes such as SiH₂F₂, SiH₂1₂, SiH₂CI₂, SiHCl₃, SiH₂Br₂and SiHBr₃, which contain hydrogen atom as the constituent element and which are in the gaseous state or gasifiable substances. The use of the gaseous or gasifiable hydrogen-containing halides is particularly advantageous since, at the time of forming a light receiving layer, the hydrogen atoms, which are extremely effective in view of controlling the electrical or photoelectrographic properties, can be introduced into that layer together with halogen atoms.

0179The structural introduction of hydrogen atoms into the layer can be carried out by introducing, in addition to these gaseous starting materials, H₂, or silicon hydrides such as SiH₄, SiH₆, Si₃H₆, Si₄H,o, etc. into the deposition chamber together with a gaseous or gasifiable silicon-containing substance for supplying Si, and producing a plasma atmosphere with these gases therein.

0180The amount of the hydrogen atoms (H) and/or the amount of the halogen atoms (X) to be contained in the layer are adjusted properly by controlling related conditions, for example, the temperature of a substrate, the amount of a gaseous starting material capable of supplying the hydrogen atoms or the halogen atoms into the deposition chamber and the electric discharging power.

0181In order to incorporate the group III atoms or the group V atoms, and, oxygen atoms, nitrogen atoms or carbon atoms in the IR layer, the charge injection inhibition layer or the photoconductive layer using the glow discharging process, reactive sputtering process or ion plating process, the starting material capable of supplying the group III or group V atoms, and, the starting material capable of supplying oxygen atoms, nitrogen atoms or carbon atoms are selectively used together with the starting material for forming the IR layer, the charge injection inhibition layer or the photoconductive layer upon forming such layer while controlling the amount of them in that layer to be formed.

0182As the starting material to introduce the atoms (O,N,C), many gaseous or gasifiable substances containing any of oxygen, carbon, and nitrogen atoms as the constituent atoms can be used. Likewise, as for the starting material to introduce the group III or group V atoms, many gaseous or gasifiable substances can be used.

0183For example, referring to the starting material for introducing oxygen atoms, most of those gaseous or gasifiable materials which contain at least oxygen atoms as the constituent atoms can be used.

0184And, it is possible to use a mixture of a gaseous starting material containing silicon atoms (Si) as the constituent atoms, a gaseous starting material containing oxygen atoms (O) as the constituent atom and, as required, a gaseous starting material containing hydrogen atoms (H) and/or halogen atoms (X) as the constituent atoms in a desired mixing ratio, a mixture of gaseous starting material containing silicon atoms (Si) as the constituent atoms and a gaseous starting material containing oxygen atoms (O) and hydrogen atoms (H) as the constituent atoms in a desired mixing ratio, or a mixture of gaseous starting material containing silicon atoms (Si) as the constituent atoms and a gaseous starting material containing silicon atoms (Si), oxygen atoms (O) and hydrogen atoms (H) as the constituent atoms.

0185Further, it is also possible to use a mixture of a gaseous starting material containing silicon atoms (Si) and hydrogen atoms (H) as the constituent atoms and a gaseous starting material containing oxygen atoms (O) as the constituent atoms.

0186Specifically, there can be mentioned, for example, oxygen (0₂), ozone (0₃), nitrogen monoxide (NO), nitrogen dioxide (N0₂), dinitrogen oxide (N₂0), dinitrogen trioxide (N₂0₃), dinitrogen tetraoxide (N₂0₄), dinitrogen pentoxide (N₂0₅), nitrogen trioxide (N0₃), lower siloxanes comprising silicon atoms (Si), oxygen atoms (O) and hydrogen atoms (H) as the constituent atoms, for example, disiloxane (H₃SiOSiH₃) and trisiloxane (H₃SiOSiH₂0SiH₃), etc.

0187Likewise, as the starting material for introducing nitrogen atoms, most of gaseous or gasifiable materials which contain at least nitrogen atoms as the constituent atoms can be used.

0188For instance, it is possible to use a mixture of a gaseous starting material containing silicon atoms (Si) as the constituent atoms, a gaseous starting material containing nitrogen atoms (N) as the constituent atoms and, optionally, a gaseous starting material containing hydrogen atoms (H) and/or halogen atoms (X) as the constituent atoms in a desired mixing ratio, or a mixture of a starting gaseous material containing silicon atoms (Si) as the constituent atoms and a gaseous starting material containing nitrogen atoms (N) and hydrogen atoms (H) as the constituent atoms also in a desired mixing ratio.

0189Alternatively, it is also possible to use a mixture of a gaseous starting material containing nitrogen atoms (N) as the constituent atoms and a gaseous starting material containing silicon atoms (Si) and hydrogen atoms (H) as the constituent atoms.

0190The starting material that can be used effectively as the gaseous starting material for introducing the nitrogen atoms (N) used upon forming the layer containing nitrogen atoms can include gaseous or gasifiable nitrogen, nitrides and nitrogen compounds such as azide compounds comprising N as the constituent atoms or N and H as the constituent atoms, for example, nitrogen (N₂), ammonia (NH₃), hydrazine (H₂NNH₂). hydrogen azide (HN₃) and ammonium azide (NH4N3). In addition, nitrogen halide compounds such as nitrogen trifluoride (F₃N) and nitrogen tetrafluoride (F₄N₂) can also be mentioned in that they can also introduce halogen atoms (X) in addition to the introduction of nitrogen atoms (N).

0191Further, as for the starting material for introducing carbon atoms, gaseous or gasifiable materials containing carbon atoms as the constituent atoms can be used.

0192And it is possible to use a mixture of gaseous starting material containing silicon atoms (Si) as the constituent atoms, gaseous starting material containing carbon atoms (C) as the constituent atoms and, optionally, gaseous starting material containing hydrogen atoms (H) and/or halogen atoms (X) as the constituent atoms in a desired mixing ratio, a mixture of gaseous starting material containing silicon atoms (Si) as the constituent atoms and gaseous starting material containing carbon atoms (C) and hydrogen atoms (H) as the constituent atoms also in a desired mixing ratio, or a mixture of gaseous starting material containing silicon atoms (Si) as the constituent atoms and gaseous starting material comprising silicon atoms (Si).

0193Those gaseous starting materials that are effectively usable herein can include gaseous silicon hydrides containing carbon atoms (C) and hydrogen atoms (H) as the constituent atoms, such as silanes, for example, SiH₄, Si₂H₆, Si₃H₈ and Si₄H₁₀, as well as those containing carbon atoms (C) and hydrogen atoms (H) as the constituent atoms, for example, saturated hydrocarbons of 1 to 4 carbon atoms, ethylenic hydrocarbons of 3 to 4 carbon atoms and acetylenic hydrocarbons of 2 to 3 carbon atoms.

0194Specifically, the saturated hydrocarbons can include methane (CH₄), ethane (C₂Hs), propane (C₃H₈), n-butane (n-C₄H₁₀) and pentane (C₅H₁₂), the ethylenic hydrocarbons can include ethylene (C₂H₄), propylene (C₃H₆), butene-1 (C₄H₈), butene-2 (C₄H₈), isobutylene (C₄H₈) and pentene (C₅H₁₀) and the acetylenic hydrocarbons can include acetylene (C2H2), methylacetylene (C₃H₄) and butine (C₄H₆).

0195The gaseous starting material containing silicon atoms (Si), carbon atoms (C) and hydrogen atoms (H) as the constituent atoms can include silicided alkyls, for example, Si(CH₃)₄ and Si(C₂H₅)₄. In addition to these gaseous starting materials, H₂ can of course be used as the gaseous starting material for introducing hydrogen atoms (H).

0196In order to form the IR layer, the charge injection prohibition layer or the photoconductive layer incorporated with the group III or group V atoms using the glow discharging process, reactive sputtering process or ion plating process, the starting material for introducing the group III or group V atoms is used together with the starting material for forming such upon forming that layer while controlling the amount of them in the layer to be formed.

0197For instance, in the case of forming a layer composed of poly-Si(H,X) or of A-Si(H,X) containing the group III or group V atoms, namely poly-SiM(H,X) or A-SiM(H,X) wherein M stands for the group III or group V atoms, by using the glow discharging, the starting gases material for forming such layer are introduced into a deposition chamber in which a substrate being placed, optionally being mixed with an inert gas such as Ar or He in a predetermined mixing ratio, and the thus introduced gases are exposed to the action of glow discharge to thereby cause a gas plasma resulting in forming a layer composed of a-SiM(H,X) on the substrate.

0198Referring specifically to the boron atom introducing materials as the starting material for introducing the group III atoms, they can include boron hydrides such as B₂H₆, B₄H₁₀, B₅H₉, B₅H₁₁, B₆H₁₀, B₆H₁₂ and B₆H₁₄ and boron halides such as BF₃, BCl₃ and BBr₃. In addition, AlCl₃, CaC1₃, Ga(CH₃)₂, InCI₃, TICl₃ and the like can also be mentioned.

0199Referring to the starting material for introducing the group V atoms and, specifically, to the phosphorus atom introducing materials, they can include, for example, phosphor hydrides such as PH₃ and P₂H₆ ahd phosphor halide such as PH₄1, PF₃, PFs, PC1₃, PCl₅, PBr₃, PBr₅ and PI₃. In addition, AsH₃, AsFs, AsCl₃, AsBr₃, AsF₃, SbH₃, SbF₃, SbFs, SbCl₃, SbCls, BiH₃, SiCl₃ and BiBr₃ can also be mentioned to as the effective starting material for introducing the group V atoms.

0200The amount of the group III or group V atoms to be contained in the IR layer, the charge injection prohibition layer or the photoconductive layer are adjusted properly by controlling the related conditions, for example, the temperature of a substrate, the amount of a gaseous starting material capable of supplying the group III or group V atoms, the gas flow rate of such gaseous starting material, the discharging power, the inner pressure of the deposition chamber, etc.

0201The conditions upon forming the constituent layers of the light receiving member of the invention, for example, the temperature of the support, the gas pressure in the deposition chamber, and the electric discharging power are important factors for obtaining the light receiving member having desired properties and they are properly selected while considering the function of each of the layers to be formed. Further, since these layer forming conditions may be varied depending on the kind and the amount of each of the atoms contained in the layer, the conditions have to be determined also taking the kind or the amount of the atoms to be contained into consideration.

0202Specifically, the conditions upon forming the constituent layer of the light receiving member of this invention are different according to the kind of the material with which the layer is to be constituted.

0203In the case of forming the charge injection inhibition layer which is constituted with a poly-Si material, and the IR layer which is constituted also with a poly-Si material in case where necessary, the relationship between the temperature of a substrate and the electrical discharging power is extremely important.

0204That is, when the temperature of the substrate is adjusted to be in the range from 200 to 350 _°C, the electrical discharging power is adjusted to be preferably in the range from 1100 to 5000 W/cm², and more preferably, in the range 1500 to 4000 W/cm^2. And, when the temperature of the substrate is adjusted to be in the range from 350 to 700 _°C, the electrical discharging power is adjusted to be preferably in the range from 100 to 5000 W/cm², and more preferably in the range from 200 to 4000 W/cm².

0205And as for the gas pressure in the deposition chamber in the above case, it is preferably 10-³ to 8 x 10-¹ Torr (1 Torr = 1,333 mbar), and more preferably, 5 x 10-³ to 5 x 10-¹ Torr.

0206On the other hand, in the case of forming the photoconductive layer which is constituted with an A-Si material, and the IR layer which is constituted also with an A-Si material, the temperature of the substrate is usually from 50 to 350 °C, preferably, from 50 to 300 °C, most suitably 100 to 250 °C; the gas pressure in the deposition chamber is usually from 1 x 10-² to 5 Torr, preferably, from 1 x 10-² to 3 Torr, most suitably from 1 x 10-¹ to 1 Torr; and the electrical discharging power is preferably from 10 to 1000 W/cm², and more preferably, from 20 to 500 W/cm².

0207In any case, the actual conditions for forming the layer such as temperature of the support, discharging power and the gas pressure in the deposition chamber cannot usually be determined with ease independent of each other. Accordingly, the conditions optimal to the layer formation are desirably determined based on relative and organic relationships for forming the corresponding layer having desired properties.

Preparation of Surface Layer

0208The surface layer 104 in the light receiving member for use in electrophotography according to this invention is constituted with an amorphous material composed of A-(Si_xC_1-x)_y : H_1-y [x>0, y<1] which contains 41 to 70 atomic % of hydrogen atoms and is disposed on the above-mentioned photoconductive layer.

0209The surface layer can be properly prepared by vacuum deposition method utilizing the discharge phenomena such as flow discharging, sputtering or ion plating wherein relevant gaseous starting materials are selectively used as well as in the above-mentioned cases for preparing the photoconductive layer.

0210However, the glow discharging method or sputtering method is suitable since the control for the condition upon preparing the surface layer having desired properties are relatively easy, and hydrogen atoms and carbon atoms can be introduced easily together with silicon atoms. The glow discharging method and the sputtering method may be used together in on identical system.

0211Basically, when a layer constituted with A-(si_xC_1-x)_y : H_1-y is formed, for example, by the glow discharging method, gaseous starting material capable of supplying silicon atoms (Si) are introduced together with a gaseous starting material for introducing hydrogen atoms (H) and/or halogen atoms (X) into a deposition chamber the inside pressure of which can be reduced, glow discharge is generated in the edeposition chamber, and a layer constituted with A-(Si_xC_1-x)_y : H_1-y containing 41 to 70 atomic % of hydrogen atoms is formed on the surface of a substrate placed in the deposition chamber.

0212As for the gaseous starting materials for supplying silicon atoms (Si) and/or hydrogen atoms (H), the same gaseous materials as mentioned in the above cases for preparing photoconductive layer can be used as long as they do not contain any of halogen atoms, nitrogen atoms and oxygen atoms.

0213That is, the gaseous starting material usable for forming the surface layer can include almost any kind of gaseous or gasifiable materials as far as it contains one or more kinds selected from silicon atoms, hydrogen atoms and carbon atoms as the constituent atoms.

0214Specifically, for the preparation of the surface layer, it is possible to use a mixture of gaseous starting material containing silicon atoms (Si) as the constituent atoms, gaseous starting material containing carbon atoms (C) as the constituent atoms and, optionally, gaseous starting material containing hydrogen atoms (H) as the constituent atoms in a desired mixing ratio, a mixture of gaseous starting material containing silicon atoms (Si) as the constituent atoms and gaseous starting material containing carbon atoms (C) and hydrogen atoms (H) as the constituent atoms also in a desired mixing ratio, or a mixture of gaseous starting material containing silicon atoms (Si) as the constituent atoms and gaseous starting material comprising silicon atoms (Si) in the glow discharging process as described above.

0215Those gaseous starting materials that are effectively usable herein can include gaseous silicon hydrides containing carbon atoms (C) and hydrogen atoms (H) as the constituent atoms, such as silanes, for example, SiH₄, Si₂H₆, Si₃H₈ and Si₄H₁₀, as well as those containing carbon atoms (C) and hydrogen atoms (H) as the constituent atoms, for example, saturated hydrocarbons of 1 to 4 carbon atoms, ethylenic hydrocarbons of 2 to 4 carbon atoms and acetylenic hydrocarbons of 2 to 3 carbon atoms.

0216Specifically, the saturated hydrocarbons can include methane (CH₄), ethane (C₂Hs), propane (C₃H₈), n-butane (n-C4 H, o) and pentane (C₅H₁₂), the ethylenic hydrocarbons can include ethylene (C₂H₄), propylene (C₃H₆), butene-1 (C₄H₈), butene-2 (C₄H₈), isobutylene (C4 Hg) and pentene (C₅H₁₀) and the acetylenic hydrocarbons can include acetylene (C2H2), methylacetylene (C₃H₄) and butine (C₄H₆).

0217The gaseous starting material containing silicon atoms (Si), carbon atoms (C) and hydrogen atoms (H) as the constituent atoms can include silicided alkyls, for example, Si(CH₃)₄ and Si(C₂H₅)₄. In addition to these gaseous starting materials, H₂ can of course be used as the gaseous starting material for introducing hydrogen atoms (H).

0218In the case of forming the surface layer by way of the sputtering process, it is carried out by using a single crystal or polycrystalline Si wafer, a C (graphite) wafer or a wafer containing a mixture of Si and C as a target and sputtering them in a desired gas atmosphere.

0219In the case of using, for example, an Si wafer as a target, a gaseous starting material for introducing carbon atoms (C) is introduced while being optionally diluted with a dilution gas such as Ar and He into a sputtering deposition chamber thereby forming gas plasmas with these gases and sputtering the Si wafer.

0220Alternatively, in the case of using Si and C as individual targets or as a single target comprising Si and C in admixture, gaseous starting material for introducing hydrogen atoms as the sputtering gas is optionally diluted with a dilution gas, introduced into a sputtering deposition chamber thereby forming gas plasmas and sputtering is carried out. As the gaseous starting material for introducing each of the atoms used in the sputtering process, those gaseous starting materials used in the glow discharging process as described above may be used as they are.

0221The conditions upon forming the surface layer constituted with an amorphous material composed of A-(Si_xC_1-x)_y : H_1-y which contains 41 to 71 atomic % of hydrogen atoms, for example, the temperature of the substrate, the gas pressure in the deposition chamber and the electric discharging power are important factors for obtaining a desirable surface layer having desired properties and they are properly selected while considering the functions of the layer to be formed. Further, since these layer forming conditions may be varied depending on the kind and the amount of each of the atoms contained in the light receiving layer, the conditions have to be determined also taking the kind or the amount of the atoms to be contained into consideration.

0222Specifically, the temperature of the substrate is preferably from 50 to 350 ° C and, most preferably, from 100 to 300 °C. The gas pressure in the deposition chamber is preferably from 0.01 to 1 Torr and, most preferably, from 0.1 to 0.5 Torr. Further, the electrical discharging power is preferably from 10 to 1000 W/cm², and, most preferably, from 20 to 500 W/cm^2.

0223However, the actual conditions for forming the surface layer such as the temperature of a substrate, discharging power and the gas pressure in the deposition chamber can not usually be determined with ease independent of each other. Accordingly, the conditions optimal to the formation of the surface layer are desirably determined based on relative and organic relationships for forming the surface layer having desired properties.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

0224The invention will be described more specifically while referring to Examples 1 through 24, but the invention is not intended to limit the scope only to these examples.

0225In each of the examples, the light receiving layer was formed by using the glow discharging process. Figure 24 shows the apparatus for preparing the light receiving member according to this invention.

0226Gas reservoirs 2402, 2403, 2404, 2405, and 2406 illustrated in the figure are charged with gaseous starting materials for forming the respective layers in the light receiving member for use in electrophotography according to this invention, that is, for instance, SiH₄ gas (99.999% purity) in the reservoir 2402, B2 H6 gas (99.999% purity) diluted with H₂ (referred to as "B₂H₆/H₂") in the reservoir 2403, H₂ gas (99.99999% purity) in the reservoir 2404, NO gas (99.999% purity) in the reservoir 2405, and CH₄ gas (99.99% purity) in the reservoir 2406.

0227Prior to the entrance of these gases into a reaction chamber 2401, it is confirmed that valves 2422-2426 for the gas reservoirs 2402-2406 and a leak valve 2435 are closed and that inlet valves 2412-2416, exit valves 2417-2421, and sub-valves 2432 and 2433 are opened. Then, a main valve 2434 is at first opened to evacuate the inside of the reaction chamber 2401 and gas piping.

0228Then, upon observing that the reading on the vacuum 2436 became about 5 x 10-⁶ Torr, the sub-valves 2432 and 2433 and the exit valves 2417 through 2421 are closed.

0229Now, reference is made to the example shown in Figure 1 (A) in the case of forming the photo receiving layer on an AI cylinder as a substrate 3437.

0230At first, SiH₄ gas from the gas reservoir 2402, B₂H₆/H₂ gas from the gas reservoir 2403, H₂ gas from the gas reservoir 2404, and NO gas from the gas reservoir 2505 are caused to flow into mass flow controllers 2407, 2408, 2409, and 2410 respectively by opening the inlet valves 2412, 2413, 2414, and 2415, controlling the pressure of exit pressure gauges 2427, 2428, 2429, and 2430 to 1 kg/cm^2. Subsequently, the exit valves 2417, 2418, 2419, and 2420, and the sub-valve 2432 are gradually opened to enter the gases into the reaction chamber 2401. In this case, the exit valves 2417, 2418, 2419, and 2420 are adjusted so as to attain a desired value for the ratio among the SiH₄ gas flow rate, NO gas flow rate, CH₄ gas flow rate, and B₂H₆/H₂ gas flow rate, and the opening of the main valve 2434 is adjusted while observing the reading on the vacuum gauge 2436 so as to obtain a desired value for the pressure inside the reaction chamber 2401. Then,after confirming that the temperature of the 2437 has been set by a heater 2448 within a range from 50 to 350 _°C, a power source 2440 is set to a predetermined electrical power to cause glow discharging in the reaction chamber 2401 while controlling the flow rates of NO gas and/or B₂Hs/H₂ gas in accordance with a previously designed variation coefficient curve by using a microcomputer (not shown), thereby forming, at first, a charge injection inhibition layer 102 containing oxygen atoms and boron atoms on the substrate cylinder 2437. When the layer 102 has reached a desired thickness, the exit valves 2418 and 2420 are completely closed to stop B₂Hs/H₂ gas and NO gas into the deposition chamber 2401. At the same time, the flow rate of SiH₄ gas and the flow rate of H₂ gas are controlled by regulating the exit valves 2417 and 2419 and the layer formation process is continued to thereby form a photoconductive layer without containing both oxygen atoms and boron atoms having a desired thickness on the previously formed charge injection inhibition layer.

0231In the case of forming a photoconductive layer containing oxygen atoms and/or boron atoms, the flow rate for the gaseous starting material to supply such atoms in appropriately controlled in stead of closing the exit valves 2418 and/or 2420.

0232In the case where halogen atoms are incorporated in the charge injection inhibition layer 102 and the photoconductive layer 103, for example, SiF₄ gas is fed into the reaction chamber 2401 in addition to the gases as mentioned above.

0233And it is possible to further increase the layer forming speed according to the kind of a gas to be selected. For example, in the case where the charge injection inhibition layer 102 and the photoconductive layer 103 are formed using Si2 H6 gas in stead of the SiH₄ gas, the layer forming speed can be increased by a few holds and as a result, the layer productivity can be rised.

0234In order to form the surface layer 104 or the resulting photoconductive layer, for example, SiH₄ gas, CH₄ gas and if necessary, a dilution gas such as H₂ gas are introduced into the reaction chamber 2401 by operating the corresponding valves in the same manner as in the case of forming the photoconductive layer and glow discharging is caused therein under predetermined conditions to thereby form the surface layer.

0235In that case, the amount of the carbon atoms to be incorporated in the surface layer can be properly controlled by appropriately changing the flow rate for the SiH₄ gas and that for the CH₄ gas respectively to be introduced into the reaction chamber 2401. As for the amount of the hydrogen atoms to be incorporated in the surface layer, it can be properly controlled by appropriately changing the flow rate of the H₂ gas to be introduced into the reaction chamber 2401.

0236All of the exit valves other than those required for upon forming the respective layers are of course closed. Further, upon forming the respective layers, the inside of the system is once evacuated to a high vacuum degree as required by closing the exit valves 2417 through 2421 while entirely opening the sub-valve 2432 and entirely opening the main valve 2434.

0237Further, during the layer forming operation, the AI cylinder as substrate 2437 is rotated at a predetermined speed by the action of the motor 2439.

Example 1

0238A light receiving member for use in electrophotography having a light receiving layer disposed on an AI cylinder having a mirror grinded surface was prepared under the layer forming conditions shown in Table 1 using the fabrication apparatus shown in Figure 24.

0239And, a sample having only a surface layer on the same kind AI cylinder and another sample having only a charge injection inhibition layer on the same kind AI cylinder respectively as in the above case were prepared respectively in the same manner for forming the surface layer and in the same manner for forming the charge injection prohibition layer in the above case using the same kind fabrication apparatus as shown in Figure 24.

0240For the resulting light receiving member (hereinafter, this kind light receiving member is referred to as "drum"), it was set with the conventional electrophotographic copying machine, and electrophotographic characteristics such as initial electrification efficiency, residual voltage and appearance of a ghost were examined, then decrease in the electrification efficiency, deterioration on photosensitivity and increase of defective images after 1,500 thousand times repeated shots were respectively examined.

0241Further, the situation of an image flow on the drum under high temperature and high humidity atmosphere at 35 _°C and 85% humidity was also examined.

0242As for the resulting sample having only the surface layer, upper part, middle part and lower part of its image forming part were cut off, and were engaged in quantitative analysis by the conventional organic element analyzer to analize the content of hydrogen atoms in each of the cut-off parts.

0243As for the resulting sample having only the charge injection prohibition layer, in the same way as the above sample, upper part, middle part and lower part were cut off, and were subjected to the measurement of diffraction patterns corresponding to Si (III) near 27 of the diffraction angle by the conventional X-ray diffractometer to examine the existence of crystallinity.

0244The results of the various evaluations, the results of the quantitative analysis of the content of the hydrogen atoms, and the situations of crystallinity for the samples are as shown in Table 2.

0245As Table 2 illustrates, considerable advantages on items of initial electrification efficiency, effective image flow and sensitivity deterioration were acknowledged.

Comparative Example 1

0246Except that the layer forming conditions changed as shown in Table 3, the drum and the sample were made under the same fabrication apparatus and manner as Example 1 and were provided to examine the same items. The results are shown in Table 4. As the Table 4 illustrates, much defects on various items were acknowledged compared to the case of Example 1.

Example 2

0247A light receiving member for use in electrophotography having a light receiving layer 100 disposed on an AI cylinder having a mirror grinded surface was prepared under the layer forming conditions shown in Table 5 using the fabrication apparatus shown in Figure 24.

0248And a sample having only a surface layer on the same kind AI cylinder as in the above case was prepared in the same manner for forming the surface layer in the above case using the same kind fabrication apparatus as shown in Figure 24.

0249Likewise, another sample having only a charge injection prohibition layer was prepared.

0250For the resulting light receiving member, it was set with the conventional electrophotographic copying machine, and electrophotographic characteristics such as initial electrification efficiency, residual voltage and appearance of a ghost were examined, then decrease in the electrification efficiency, deterioration on photosensitivity and increase of defective images after 1,500 thousand times repeated shots were respectively examined.

0251Further, the situation of an image flow or the drum under high temperature and high humidity atmosphere at 35 _°C and 85% humidity was also examined.

0252As for the resulting former sample, a middle part was cut off and subjected to the analysis of the component's thicknesswise distribution by IMA.

0253Then, a middle part was cut off from the drum, and it was subjected to the analysis of the element's thicknesswise distribution by IMA.

0254As for the resulting former sample, upper part, middle part and lower part of its image forming part were cut off, and were engaged in quantitative analysis by the conventional organic element analyzer to analize the content of hydrogen atoms in each of the cut-off parts.

0255As for the latter sample, in the same way as the above case, upper part, middle part and lower part were cut off, and were subjected to the measurement of diffraction patterns corresponding to Si (III) near 27_° of the diffraction angle by the conventional X ray diffractometer to examine the existence of crystallinity.

0256The results of the various evaluations, the results of the quantitative analysis of the content of the hydrogen atoms and the situation of crystallinity for the samples are shown in Table 6.

0257And, the elements profiles in the thicknesswise direction of the boron atoms (B) and the oxygen atoms (O) are shown in Figure 27.

0258As Table 6 illustrates, considerable advantages on items of initial electrification efficiency, effective image flow and sensitivity deterioration were acknowledged.

Example 3 (containing Comparative Example 2)

0259Multiple drums and samples for analysis were provided under the same conditions as in Example 1, except the conditions for forming a surface layer were changed to those shown in Table 7.

0260As a result of subjecting these drums and samples to the same evaluations and analyses as in Example 1, the results shown in Table 8 were obtained.

Example 4

0261With the layer forming conditions for a photoconductive layer changed to the figures of Table 9, multiple drums having a light receiving layer under the same conditions as in Example 1 were provided. These drums were examined by the same procedures as in Example 1. The results are shown in Table 10.

Example 5

0262With the layer forming conditions for a charge injection inhibition layer changed to the figures of Table 11, multiple drums having a light receiving layer and samples having only a charge injection prohibition layer were provided under the same conditions as in Example 1. And they were examined by the same procedures as in Example 1. The results are shown in Table 12.

Example 6

0263With the layer forming conditions for a charge injection inhibition layer changed to the figures of Table 13, multiple drums having a light receiving layer and samples having only a charge injection prohibition layer were provided under the same conditions as in Example 1. And they were examined by the same procedures as in Example 1. The results are shown in Table 14.

Example 7

0264There were prepared multiple light receiving members respectively having a contact layer formed under the different layer forming conditions as shown in Table 15 and a light receiving layer formed under the same layer forming conditions as in Example 1 respectively on the same kind AI cylinder as in Example 1.

0265And samples having only a contact layer were prepared in the same procedures as in the above case.

0266As for the resulting light receiving members, there were evaluated by the same procedures as in Example 1. As for the resulting samples, they were subjected to the measurement of diffraction patterns corresponding to Si (III) near 27_° of the diffraction angle by the conventional X-ray diffractometer to examine the existence of crystallinity.

0267The results are shown in Table 16.

Example 8

0268There were prepared multiple light receiving members respectively having a contact layer formed under the different layer forming conditions as shown in Table 17 and a light receiving layer formed under the same layer forming conditions as in Example 1 respectively on the same kind AI cylinder as in Example 1.

0269They were evaluated by the same procedures as in Example 1.

0270The results are shown in Table 18.

Example 9

0271The mirror grinded cylinders were supplied for grinding process of cutting tool of various degrees. With the patterns of Figure 25, various cross section patterns as described in Table 19 multiple cylinders were provided. These cylinders were set to the fabrication apparatus of Figure 24 accordingly, and used to produce drums under the same layer forming conditions of Example 1. The resulting drums were evaluated with the conventional electrophotographic copying machine having digital exposure functions and using semiconductor laser of 780 nm wavelength. The results are shown in Table 20.

Example 10

0272The surface of mirror grinded cylinder was treated by dropping lots of bearing balls thereto to thereby form uneven shape composed of a plurality of fine dimples at the surface, and multiple cylinders having a cross section form of Figure 26 and of a cross section pattern of Table 21 were provided. These cylinders were set to the fabrication apparatus of Figure 24 accordingly and used for the preparation of drums under the same layer forming conditions of Example 1. The resulting drums are evaluated with the conventional electrophotographic copying machine having digital exposure functions and using semiconductor laser of 780 nm wavelength The results are shown in Table 22.

Example 11

0273A light receiving member for use in electrophotography having a light receiving layer disposed on an AI cylinder having a mirror grinded surface was prepared under the layer forming conditions shown in Table 23 using the fabrication apparatus shown in Figure 24.

0274And, a sample having only a surface layer on the same kind AI cylinder, another sample having only a charge injection inhibition layer on the same kind AI cylinder and further sample having only an IR layer on the same kind AI cylinder respectively as in the above case were prepared respectively in the same manners for forming the surface for forming the charge injection inhibition layer and for forming the IR layer in the above case using the same kind fabrication apparatus as shown in Figure 24.

0275For the resulting light receiving member, it was set with the conventional electrophotographic copying machine, and electrophotographic characteristics such as initial electrification efficiency, residual voltage and appearance of a ghost were examined, then decrease in the electrification efficiency, deterioration on photosensitivity and increase of defective images after 1,500 thousand times repeated shots were respectively examined.

0276Further, the situation of an image flow on the drum under high temperature and high humidity atmosphere at 35 _°C and 85% humidity was also examined.

0277As for the resulting first sample having only the surface layer, upper part, middle part and lower part of its image forming part were cut off, and were engaged in quantitative analysis by the conventional organic element analyzer to analize the content of hydrogen atoms in each of the cut-off parts.

0278As for the resulting second sample having only the charge injection prohibition layer and the resulting third sample having only the IR layer, in the same way as the above sample, upper part, middle part and lower part were cut off for each sample, and were subjected to the measurement of diffraction patterns corresponding to Si (III) near 27_° of the diffraction angle by the conventional X-ray diffractometer to examine the existence of crystallinity.

0279The results of the various evaluation, the results of the quantitative analysis of the content of the hydrogen atoms, and the situations of crystallinity for the samples are as shown in Table 24.

0280As Table 24 illustrates, considerable advantages on items of initial electrification efficiency, effective image flow and sensitivity deterioration were acknowledged.

Comparative Example 3

0281Except that the layer forming conditions changed as shown in Table 25, the drums and the samples were made under the same fabrication apparatus and manner as Example 1 and were provided to examine the same items. The results are shown in Table 26. As the Table 26 illustrates, much defects on various items were acknowledged compared to the case of Example 11.

Example 12

0282A light receiving member for use in electrophotography having a light receiving layer disposed on an AI cylinder having a mirror grinded surface was prepared under the layer forming conditions shown in Table 27 using the fabrication apparatus shown in Figure 24.

0283And, a sample having only a surface layer on the same kind AI cylinder, another sample having only a charge injection prohibition layer on the same kind AI cylinder and further sample having only an IR layer on the same kind AI cylinder respectively as in the above case were provided.

0284For the resulting light receiving member, it was set with the conventional electrophotographic copying machine, and electrophotographic characteristics such as initial electrification efficiency, residual voltage and appearance of a ghost were examined, then decrease in the electrification efficiency, deterioration on photosensitivity and increase of defective images after 1,500 thousand times repeated shots were respectively examined.

0285Further, the situation of an image flow on the drum under high temperature and high humidity atmosphere at 35 _°C and 85% humidity was also examined.

0286Then, a middle part was cut off from the above drum and engaged in quantitative analysis by IMA to analize the content of the elements in the thicknesswise direction.

0287As for the resulting first sample having only the surface layer, upper part, middle part and lower part of its image forming part were cut off, and were engaged in quantitative analysis by the conventional organic element analyzer to analize the content of hydrogen atoms in each of the cut-off parts.

0288As for the resulting second sample having only the charge injection prohibition layer and the resulting third sample having only the IR layer, in the same way as the above sample, upper part, middle part and lower part were cut off for each sample, and were subjected to the measurement of diffraction patterns corresponding to Si (III) near 27_° of the diffraction angle by the conventional X-ray diffractometer to examine the existence of crystallinity.

0289The results of the various evaluations, the results of the quantitative analysis of the content of the hydrogen atoms, and the situations of crystallinity for the samples are as shown in Table 28.

0290And, the element profiles in the thicknesswise direction of the boron atoms (B) and the oxygen atoms (O) for the charge injection inhibition layer and the element profile of the germanium atoms (Ge) for the IR layer are shown in Figure 28.

0291As Table 28 and Figure 28 illustrate, considerable advantages on items of initial electrification efficiency, image flow, residual voltage, ghost, defective image, increase in the defective image, and interference fringe were acknowledged.

Example 13 (containing Comparative Example 4)

0292Multiple drums and samples for analysis were provided under the same conditions as in Figure 11, except the conditions for forming a surface layer were changed to those shown in Table 29.

0293As a result of subjecting these drums and samples to the same evaluations and analyses as in Example 11, the results shown in Table 30 were obtained.

Example 14

0294With the layer forming conditions for a photoconductive layer changed to the figures of Table 31, multiple drums having a light receiving layer were provided under the same conditions as in Example 11. These drums were examined by the same procedures as in Example 11. The results are shown in Table 32.

Example 15

0295The same procedures of Example 11 were repeated, except that the layer forming conditions for forming a charge injection inhibition layer were changed as shown in Table 33, to thereby prepare multiple drums and samples having only a charge injection inhibition layer.

0296These drums and samples were examined by the same procedures as in Example 11. The results are shown in Table 34.

Example 16

0297The same procedures of Example 11 were repeated, except that the layer forming conditions for forming a charge injection inhibition layer were changed as shown in Table 35, to thereby prepare multiple drums and samples having only a charge injection inhibition layer.

0298These drums and samples were examined by the same procedures as in Example 11. The results are shown in Table 36.

Example 17

0299The same procedures of Example 11 were repeated, except that the layer forming conditions for forming an IR layer were changed as shown in Table 37, to thereby prepare multiple drums and samples having only an IR layer.

0300The resulting drums were examined by the same procedures as in Example 11.

0301As for the resulting samples, upper part, middle part and lower part were cut off for each sample, and were subjected to the measurement of diffraction patterns corresponding to Si (III) near 27 of the diffraction angle by the conventional X-ray diffractometer to examine the existence of crystallinity.

0302The results are shown in Table 38.

Example 18

0303The same procedures of Example 11 were repeated, except that the layer forming conditions for forming an IR layer were changed as shown in Table 39, to thereby prepare multiple drums and samples having only an IR layer.

0304The resulting drums were examined by the same procedures as in Example 11.

0305As for the resulting samples, upper part, middle part and lower part were cut off for each sample, and were subjected to the measurement of diffraction patterns corresponding to Si (III) near 27 of the diffraction angle by the conventional X-ray diffractometer to examine the existence of crystallinity.

0306The results are shown in Table 40.

Example 19

0307The same procedures of Example 11 were repeated, except that the layer forming conditions for forming an IR layer were changed as shown in Table 41, to thereby prepare multiple drums and samples having only an IR layer.

0308The resulting drums were examined by the same procedures as in Example 11.

0309As for the resulting samples, upper part, middle part and lower part were cut off for each sample, and were subjected to the measurement of diffraction patterns corresponding to Si (III) near 27 of the diffraction angle by the conventional X-ray diffractometer to examine the existence of crystallinity.

0310The results are shown in Table 42.

Example 20

0311The same procedures of Example 11 were repeated, except that the layer forming conditions for forming an IR layer were changed as shown in Table 43, to thereby prepare multiple drums and samples having only an IR layer.

0312The resulting drums were examined by the same procedures as in Example 11.

0313As for the resulting samples, upper part, middle part and lower part were cut off for each sample, and were subjected to the measurement of diffraction patterns corresponding to Si (III) near 27 of the diffraction angle by the conventional X-ray diffractometer to examine the existence of crystallinity.

0314The results are shown in Table 44.

Example 21

0315On the same kind AI cylinder as in Example 1, a contact layer was formed under the layer forming conditions shown in Table 45, and a light receiving layer was formed on the contact layer by the same procedures as Example 11. And a sample having only a contact layer was also provided.

0316The resulting drums were examined by the same procedures as in Example 11.

0317As for the resulting examples, a part thereof was cut off for each sample, and was subjected to the measurement of diffraction patterns corresponding to Si (III) near 27 of the diffraction angle by the conventional X-ray diffractometer to examine the existence of crystallinity.

0318The results are shown in Table 46.

Example 22

0319On the same kind AI cylinder as in Example 1, a contact layer was formed under the layer forming conditions shown in Table 47, and a light receiving layer was formed on the contact layer by the same procedures as Example 11. And a sample having only a contact layer was also provided.

0320The resulting drums were examined by the same procedures as in Example 11.

0321As for the resulting samples, a part thereof was cut off for each sample, and was subjected to the measurement of diffraction patterns corresponding to Si (III) near 27° of the diffraction angle by the conventional X-ray diffractometer to examine the existence of crystallinity.

0322The results are shown in Table 46.

Example 23

0323The mirror grinded AI cylinders were supplied for further grinding process with the use of a cutting tool having various angles. With the cross section form of Figure 25 and the cross section patterns, multiple cylinders were provided. These cylinders were set to the fabrication apparatus of Figure 24 accordingly to prepare drums by the same procedures as in Example 11. The resulting drums were evaluated with the conventional electrophotographic copying machine having digital exposure functions and using semiconductor laser of 780 nm wavelength.

0324The results are shown in Table 50.

Example 24

0325The mirror grinded AI cylinders were engaged in further surface treatment to form uneven shape composed of a plurality of fine dimples at the surface, and multiple cylinders having a cross section form of Figure 26 and of a cross section pattern of Table 51 were provided. These cylinders were set to the fabrication apparatus of Figure 24 accordingly and used for the preparation of drums under the same layer forming conditions of Example 11. The resulting drums are evaluated with the conventional electrophotographic copying machine having digital exposure functions and using semiconductor laser of 780 nm wavelength. The results are shown in Table 52.

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0327Another aspect of the invention provides an electrophotographic member comprising a photoconductive layer on a substrate, the substrate having a roughened surface such that interference fringe patterns in the images produced on the electrophotographic member are substantially reduced.

0328The roughened surface may take the form of V-shaped grooves in the surface, preferably having a pitch of 0.3 to 500 µm, more preferably 1.0 to 200 µm, and most preferably 5.0 to 50 µm, and a depth of 0.1 to 5.0 µm, more preferably 0.3 to 3.0 µm, and most preferably 0.6 to 2.0 µm.

0329Alternatively, the roughened surface may take the form of fine spherical dimples in the surface, suitably achieved by the impact with the surface of rigid true spheres.