Optical recording material composed of antimony-tin alloy containing third element

[Detailed Description of the Invention]

[Industrial Application] The present invention relates to an antimony tin alloy useful to optical record. [Description of the Prior Art] The thin film optical recording layer which uses the phase transition to the crystal from a chalcogen-ized thin film and a non-fixed form was the theme of the research from [ many of ] the start of the 1970s. The focus was united with the optical recording layer for which the early concern can re-use it by "it is eliminable" and it since the phase transition to the crystal from a non-fixed form is a reversible process fundamentally. The low comparatively long-term laser pulse of an output is used in order [ that it is enough in order that a spot may crystallize the local spot on a layer below to the melting point ] to carry out time heating. These crystal spots can be heated by the laser pulse of the short period of a subsequently more high output more than the melting point of a crystal spot, and structure of a spot can be made random. This layer is a termination of a laser pulse and is designed enough. [ being frozen in order that the structure where the cooling rate of the heated spot was made random may attain a formless state ] In this way, by adjusting a laser output and a period, the state of the selected field on a layer can be changed between a formless state and a crystal state, and the pattern of formless and a crystal spot which can be used for information storage can be made. Since the phase transition is reversible, this pattern can be replaced by a recorded pattern which could erase and is different. Theoretically, this elimination-write-in cycle can be performed any number of times. It comes the above-mentioned write-in 1 elimination letter, and very few substances for the optical recording layer whose lump cycle is a thing of practical use are known. The eliminable layer-change type optical recording layer is not commercialized. The optical recording layer in which elimination of antimony indium and an antimony indium tin alloy of a certain kind is possible is indicated by the European Patent application No. 0184452. It is said that information storage and elimination are attained by changing a layer between two different crystal states. Generally, before these layers can record information, they are manufactured in the formless state where it should be converted into one of the two crystal states at first. It is said that extensive heat treatment or the state attained by any of laser exposure they are over a long period of time where it was crystallized has reflectance lower than a formless state. The example shows that the substance indicated there has a very late crystallization speed. The unsuitable thing is taught in order that the optical recording material indicated there may use this application by the transition mechanism to the crystal from a non-fixed form further, since the formless state is generally unstable. In this way, since transition to the crystal from a non-fixed form is slow and the formless state is unstable, the alloy indicated by this literature does not fit written-in type record once. Many attentions are turned to what is called a "- time writing type" thin film optical recording layer again. - Time writing means simply what a layer can record only once. Such a layer cannot be eliminated and cannot be re-used because of the next record. Since the thin film optical recording layer is generally formless when manufactured, it is desirable to use a crystallization process for a - time write-in layer as a record process. However, the problem of late crystallization bars achievement of a high data rate by many publicly known substances. The high data rate is important because of the 1-time write-in layer designed in order to use it by computer. In this way, essential difficulty is too usually low [ the speed of crystallization of many studied layers ]. It is desirable to have a layer which may be crystallized by the laser pulse shorter than Microsecond (muS) for practical application. Now, few substances show such capability. About some substances (for example, Te-3n alloy) which have a high crystallization speed, data-hold time is not often suitable because of the instability of a formless state. the crystallization speed in this way in which the prior art of a problem is smaller than a1.0microsecond, and b -- good corrosiveness-proof and C -- it is not providing the 1-time writing type optical recording layer which has the combination of a stable formless state, d high speed, and high-density-recording capability. The antimony tin-Kerr alloy for optical record is indicated by JP,62-246788,A of October 27, 1987 issue. There is no suggestion that other third element can use it with antimony tin in this gazette. [Problem(s) to be Solved by the Invention] There are needs about a highly efficient optical record substance succeedingly. [Means for solving problem] By the present invention, the formless thin film optical recording layer of the 1-time writing type of an alloy is included, antimony of quantity and a ratio and tin in which the alloy has 1 this model or the slightly bent To salify IJ chromium crystal, and 2 -- the recording material containing at least one sort of other elements (however, the element of Nuclear layer is not indium, aluminum, zinc, or germanium) is provided. In a desirable mode, the element of the addition which exists in an alloy raises the transition temperature to the crystal from a non-fixed form. The rise of the degree of Transfer pump to the crystal from a non-fixed form is important because of the long-term stability of a record substance. The recording layer which has a high transition temperature has few tendencies of transition to the crystal from a spontaneous non-fixed form. For example, it is presumed that the alloy which has the transition temperature of about (assuming that recording layer becomes useless by 11 mol of activation energy 100Kca, storage temperature 50degreeC, and 1% crystallization) 90 degreeC has about one year of storage life. If transition temperature rises to 110 degreeC, the storage life will increase in about 1500. It adds to indium, aluminum, zinc, and germanium, and cadmium, nickel, iron, manganese, copper, oxygen, niobium, and silicon are contained in the element in which raising the transition temperature to the crystal from a non-fixed form was found out. In this way, these are elements desirable for an antimony tin alloy. Probably, in other desirable modes, the record substance of the present invention shows the subcarrier improved when this record substance was used for optical record versus the noise ratio. The element of the addition in an alloy is considered that modification becomes smaller when being used, in order that the layer of an alloy may be made smooth, an alloy may be hardened more, then laser may make a crystal sign. It adds to indium and chromium, bismuth, niobium, and tungsten are contained in the element in which increasing a subcarrier versus the noise ratio of a recording layer was found out. In this way, these elements are also preferred in the present invention. The crystalline region generated by laser record with an antimony tin (2 values) and antimony tin-indium alloy, It is in the same crystal state altogether, and can distinguish from the recording layer in which typical elimination is possible as shown with the substance indicated to the above-mentioned European Patent application No. 0184452 by it. The above-mentioned recording layer which has the information which was recorded on the formless thin film optical recording layer of the alloy, and was recorded there with the form of the crystalline region in respect of everything but the present invention in this way is included, the alloy -- 1 -- antimony of quantity and a ratio and tin in which the crystalline region has a sodium chloride type or the bent To salify IJ chromium crystal, 2 [ and ] -- the recorded material containing at least one sort of other elements (however, the element of Nuclear layer is not indium, aluminum, zinc, or germanium) is provided. Further in respect of [ of the present invention ] others, the formless thin film optical recording layer of the 1-time writing type of a alloy is included, the alloy -- 1 -- antimony of quantity and a ratio and tin in which the sign with which crystalline laser record of the alloy was carried out has a sodium chloride type or the bent sodium chloride type crystal, They are other elements of 2 at least 1 kinds to a row (however, the element of Nuclear layer). indium, aluminum, zinc, or germanium -- it is not -- the process of carrying out easy [ of the included recording material ], And the method of recording information including the process of focusing b information abnormal-conditions laser beam to the recording layer, and forming the pattern (however, all of the crystalline regions are in the same crystal state of different reflectance from an amorphous region) of a crystal and an amorphous region in Nuclear layer is provided. [For Work ] that the alloy was found out for 1-time write-in application, a crystallization speed smaller than a 1.0microsecond, and b -- good corrosiveness-proof and C -- having the combination of a stable formless state, d high speed, and high-density-recording capability, And it was a surprising thing to have kept the combination of this character, even when an additional element was contained in this alloy. Worries were whether an additional element's being able to collapse the crystal structure of a crystalline layer, then it decreasing the useful performance of an antimony tin alloy base, or removing. However, it was an especially surprising thing that there was a case where performance actually increased. As now these artificers found out, selection of the element of the addition added by the antimony tin alloy is not restrictive, Cadmium, gallium, titanium, silicon, manganese, Tellurium, niobium, iron, copper, tungsten, a lead, molybdenum, sulfur, nickel, oxygen, selenium, thallium, arsenic, phosphorus, gold, palladium, platinum, hafnium, and vanadium can be used. The mixture of these elements is also useful. The quantity of the third element that should be contained into this alloy is dependent on the selected element and the character which should be improved. For example, from the minimum quantity that improves a subcarrier versus a noise ratio remarkably when the quantity is used for record of an alloy to the quantity to which the performance of - time writing type antimony tin character falls, That is, the element may be a range to the sodium chloride type crystal structure of antimony tin, and the point in which it begins to interfere. In a certain case, a subcarrier versus the noise ratio will be improved with few third element like 0.6 atom %. Since the transition temperature to the crystal from a non-fixed form is gone up in a still more remarkable quantity, a little more high concentration, for example, 3~35 atom %, is useful. As for at least about 3 degreeC, in the mode in which the third element raises transition temperature, it is [ the third element ] preferred to exist in sufficient quantity to raise Transition temperature. Generally the third element is little and preferably exists between 3 and 25 atom %. The optimum amount is changed depending on the selected element, and can be determined with an everyday laboratory procedure. The quantity of antimony and tin and its ratio seem to consist of a crystal into which the crystal layer of the sign by which laser record was carried out has a To salify +J Umu type crystal or the slightly perverted To salify IJ Umu type crystal structure. This is a form of a publicly known form with the art concerned, and it crystallizes the sample of the target alloy and it can determine it by conducting X-line diffraction or electron beam diffraction analysis. if -- X-line diffraction or an electronic diffraction pattern -- sodium chloride -- said - or substantially the same -- if it becomes, it will be thought that it is a To salify IJ Umu type crystal structure. Total thickness child % of antimony and tin is at least 65% preferably. The ratio of atom % of antimony to that [ % ] of tin in an alloy is between 1 and 9 preferably. In this way, a useful alloy is formula:% type % at the present invention. It can express by (E is the third element (or mixture of an element) among a formula, x, y, and 2 express atom % of the element in an alloy, the ratio of X to y is between about 1 and 9, and Z is between 0.6 and 35 atom %). Generally an alloy desirable for the third desirable element has the following composition (the next number of an element expresses atom % in an alloy). 5b66Sn28Ga6.5b58Sn32GalO,5b64Sn30Cd6 *5b52Sn39Cd9.5b50Sn34Cd16.5b68Sn8Te24 *5b61Sn26Cr13.5b67Sn29Bi4.5b63Sn27NblO. 5b62Sn27Till 5b62Sn27Si11. (Sb86Sn14) Oy. (Sb77Sn23), 0., 5b59Sn32nickel9. 5b70Sn26Fe4 *Sb66Sn25Mn9 and 5b61Sn28Cull. An optical recording layer can be manufactured with publicly known thin film self-possessed art like RF (radio frequency) from an alloy target, and DC (direct current) sputtering which uses the alloy of the present invention. Reinforcement of the sputtering method (magnetron sputtering) by applying a magnetic field can also be used. membranous thickness is dependent on compromise between factors like Every, such as contrast, sensitivity, manufacture speed, material cost, ease of control, and day Sauce- (data rate), -- several 10~ -- it may be hundreds of nm. Polyethylene terephthalate, polymethyl methacrylate, a plastic sheet like polycarbonate, a glass board, paper, and a metal plate like aluminum are contained in the base material which can be used. Information storage to the thin film top made using the alloy of the present invention is performed in the layer by focusing the Lade beam by which information abnormal conditions were carried out, and thereby, if that is not right, it will make the pattern of information form in the form of a crystallization region into a formless layer at the layer. A useful recording material becomes turn from an exterior covering layer, a thin film optical recording layer, and a base from the outer surface of a recording material. Corresponding to a drive signal, the intensity of the diode record beam which focused to the recording layer is modulated by the information which should be recorded. A recording material rotates for example, by fixed speed and 1800 revolution per minute (rpm) during record. As a result, it is recorded on an optical recording layer with the form of the crystallization region where the track of information was chosen. A record spot crosses a recording material to a radial inner side, and is scanned, and, thereby, information is recorded along a spiral or a concentric circle track as record is continued. The size and the interval of an information sign which were recorded change according to the contents of information of a record laser drive signal like the position of the radial direction of a recording material. The recording material which has the information recorded in this way between lead pack processes rotates at the same speed as having rotated between record processes. Optical path of a read-out laser beam focuses at the reproduction spot of a recording material by quantity Teacup Open Lorenz. After interfering in the radiation which a recording material is a reflected type thing, then forms a reproduction spot with the information sign recorded on the optical recording material, through a quantity numerical value opening lens, it reflects and it returns. A lens is turned on the detector which makes an electric reproduction signal corresponding to the amount of temporal responses in the radiation illumination of the reflective laser radiation which goes the reflected laser radiation into a detector (contrast). Other forms of a recording material are useful. For example, in a reflexibility base like aluminum, the recording layer which becomes both sides of a base from the alloy of the present invention can be provided. Then, a useful recording material is the aluminum with which the layer of the phase change alloy of a smooth layer and the present invention and the layer of transparent protection exterior covering were covered by both sides. In the same mode, an alloy is provided on the transparent base subsequently to both sides of a base pasted up with adhesives. In other modes, the above alloys are provided on the transparent base which forms a recording layer. Subsequently, an optical recording layer is pasted up on the recording layer of the same recording material by an adhesion layer. The thickness of an adhesion layer gives optical separation of two recording layers. In the example shown below, the sample was examined about the transition temperature to the crystal from a non-fixed form. The method is as follows. The depositing film which should be examined was placed on the heat board under a circulation nitrogen atmosphere. This film was formless at first. Temperature was raised at 10 mm K/second speed. During this heating, the regular reflectance of the surface of this layer is monitored until all of layers crystallize and reflectance reaches the maximum. Data is analyzed and the transition temperature to the crystal from a non-fixed form is obtained as a temperature when a sample reaches the half of the rate change of total internal reflection. In the following example, the alloy was examined about the dynamic state performance. In order to measure a dynamic state value in performance, the standard examination form was used. Especially the covering thing deposited on the clear glass base, and it examined it in the dynamic state examination stand. The used recording head comprised the 780-nm reading diode laser and the 33Qnm write-in diode laser using 0.55 value Open Lorenz. Reading power was 0.5 mW in the number injection of high frequency (highfrequency 1njection). The disk was examined on about 55 mm in radius, linear velocity 10 m/s, and 2.78-MHz50% duty cycle write-in frequency. A subcarrier versus the noise ratio was measured with the HP3585A spectrum analyzer who uses 30-kHz resolution bandwidth. The carrier level was measured at 2.78 MHz. 500 kHz of noise levels were measured and averaged rather than subcarrier frequency on When and in the bottom. The optimal recording power (dynamic state sensitivity) was the power by which the minimum intensity was observed about the secondary harmonics of subcarrier frequency. The following value in performance can be acquired with the arbitrary dynamic state optical record test equipments for research (research quality dynamicoptical recording test facility) which have a sufficiently low system noise level. [Example] The following example is shown in order to further explain operation of the present invention. Example 1 (a) Manufacture of an optical recording medium: Both sputtering of the alloy target of sb and Sn which comprises the mixture of the quantity of 70atom% and 30 atom %, respectively was carried out with third element;Cr, Nb, Bi, Ti, Si, or W. A sputtering system is exhausted to less than I X 10-'Torr, and it is Ar as sputtering gas to the interior of a room. It was filled up with 3mTorr. The input power of 50W was used for Sbo of a 2-inch diameter, l5no, and 3 alloy target. The third power and self-possessed time to the element target were changed in order to change quantity - of the third element in the depositing film of 7 Qn+t+ thickness. Composition of each film was determined from a self-possessed speed from each target. The film was deposited on the glass microscope slide and the 130-mm glass disk base. Subsequently, the sputtering system was returned to normal pressure and, subsequently to room temperature, the film was cooled naturally. (b) Characteristic display of an optical recording medium: The product disk base sample made from Gasla (glass base) obtained at the above-mentioned process was evaluated in [ performance / write-in ] dynamic state. In order to acquire optimal recording power (ORP) and I wave transmission pair noise ratio (CNR), a subcarrier (CARR), the written-in noise (1 To NO[SE), and the noise (UNOISE) which is not written in for the sign length of 1.8-, It determined on 10 m/S linear velocity and the 2.78M1lz record frequency in a 50% duty cycle. Record and reading were performed through the glass base. The reflectance (RFLv) of the formless film in 830nfl+ was measured with the spectrum photometer from the film side. Tracking is a problem as the reflectance of a layer is too low, for example, it is less than 15%. It is too high, for example, when it exceeds 70%, the contrast (DLT R) of the written-in field is too low. The change (DLT R) in the reflectance between the formless phase of the sign of about 1 pm size and a crystal phase was measured under 830-nm diode laser and a microscope (from the film side). When DLT R or contrast gives a good subcarrier signal, it is important. (C) Conclusion: The data about a sample is shown in the 1st table of the following. The performance of the antimony tin alloy was improved by addition of the third element at the each side. In a certain case, the transition temperature to the crystal from a non-fixed form is improved. In other cases, CNR is improved. Cr: The improvement in dynamic state record is attained by addition of Cr to a 7*5n of Sb(s)3o alloy film. What CNR and the noise which is not written in and written in will be continuously improved by addition of Cr to 17.4atom%, and will further be improved by more high-concentration Cr was shown. Bl: CNR and the noise which is not written in and written in were improved by addition of Bi in the low concentration between 0.7~4.7 atom %. The film by which sputtering was carried out at concentration higher than 5.0 atom % was crystallinity. Nb: By addition of Nb of 0.6~15.6 atom %, CNR and the noise which is not written in and written in are improved continuously. At concentration higher than 9.8atom% or it, Nb raises the transition temperature of a formless phase and improves heat stability again. T1; Ti did not give improvement by the write-in performance with concentration lower than 2.3atom% or it. The crystalline film was generated at the concentration of 3.9~6.1 atom %. Concentration higher than 8.6atom% or it improved CNR. To S Addition of Sl higher than 6.2atom% or it raised the transition temperature of the formless + eye, and improved the heat stability of the film. W: The improvement in the noise and CNR which were written in is attained by addition of tungsten to 13 and 14atom%. Tungsten concentration higher than 9.46atom% or it raises the transition temperature of a formless phase, and improves heat stability again. Pb: Addition of Pb in low concentration (1, 05~7.48atom%) to 5tltoSnzo raises the transition temperature of a formless phase to 135degreeC, and improves the heat stability of a film. The constituent of Pb concentration higher than 7.48 atom % generates a crystalline film. ! Jl voice performance is also improved by leaden addition. Low write-in noise produces a higher signal to noise ratio, and, on the other hand, sensitivity and Disturbance wave intensity do not change in essence as compared with contrast. Hf : The hafnium concentration of 1.29~8.67 atom % raises the transition temperature of a formless phase, and improves the heat stability of a film. Dynamic state performance is also improved by addition of hafnium to 8.67atom%. Low write-in noise produces a better signal to noise ratio. At the concentration of hafnium above 8.67 atom %, sensitivity becomes low too much and, as for a film, contrast (change of the reflectance between a formless phase and a crystal phase) decreases. Example 2 In another series of an example, sputtering of the alloy was carried out from the target instead of Both sputtering from two targets in the end of mixed powder, and also the sample was manufactured in the similar way. It examined about the above transition temperature, and these samples were written in with static pit tester (static pit tester), and were examined about sensitivity and contrast. A static pit tester gives the automation equipment with which micro pair coater controls a sample position, laser power, and laser pulse width. Each recording layer is exposed by a 790-nm laser diode within a static pit tester, the matrix of a spot is produced, Lade power is changed into 0.7~12 mW in that case, and pulse width is changed at 50~30.000 nanoseconds. The conformity of the recording layer for optical record is determined by measuring between, namely, the change [ the field where the sample was exposed, and an unexposed field ] in reflection between a crystal state and a formless state. In a table, Lade power required in order to write in with the pulse width for 50 nanoseconds is a measure of the sensitivity of a film. Lower power shows higher sensitivity. The ratio of antimony to tin was changed. A result is shown in a The ■ table. The n-th table 5b70Sn30 for SbX Sny+EZ A11ay-time writing type optical record Sb75Sn22Ga3 Sb66Sn28Ga6 Sb58Sn32GalO 3b60Sn22Ga18 Sb53Sn43Cd4 Sb64Sn30Cd6 Sb77Sn17Cd6 Sb52Sn39Cd9 Sb73Sn15Cd12 Sb44Sn44Cd 12 The ■ table (continuation) Sbx Sny +epsilonz For A11oy-time writing type optical record [effect of an invention] The present invention provides the optical record element of the improved character. For example, the crystal transition temperature and a subcarrier versus the noise ratio which went up are provided. 5b50Sn34Cd16 155 3Sb62Sn21Cd17 188 4Sb68Sn8Te24 125 10Sb59Sn32Ni9 109 12Sb70Sn26Fe4 110 5Sb66Sn25Mn9 136 4Sb61Sn28Cull 123 4(Sb68n32)xOy 150 2.5(Sb82Sn18)X[l'/ 160 3(Sb77Sn23)xOy 170 2.5 (Sb68Sn32>x[] y 130 3 film was manufactured by reactive sputtering.) 1 or 3% of oxygen was used between sputtering among Ar. Total Pressure was 3 mtorr. The flow velocities were 23cpm.