Material of chemical compounds with a metal in group iv a of the periodic system, nitrogen and oxygen and process for producing it
Abstract
THE INVENTION IS OF A MATERIAL WITH CHEMICAL COMPOUNDS AND AMONG THEM A METAL OF GROUP IV A OF THE PERIODIC, NITROGEN AND OXYGEN SYSTEM. IN THIS MATERIAL IT IS POSSIBLE TO ADJUST THE OPTICAL AND ELECTRIC PROPERTIES IN A WIDE INTERVAL BY MEANS OF SMALL CAVIDADES, WITHOUT HAVING TO CHANGE THE CHEMICAL COMPOSITION. THE MATERIAL IS ESPECIALLY APPROPRIATE AS A CONVERTER FOR SELECTING RADIATION IN SOLAR ENERGY AND IN THE INDUSTRY OF ELECTRICAL POWER PLANTS. IN ADDITION TO OTHER PROCESSES OF OBTAINING, IT CAN BE DEPOSITED AS A FINE LAMINILLA THROUGH REACTIVE VACUUM METALIZATION.

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13 claims: 10 independent, 3 dependent
- 1ES 2 149 342 T3 REIVINDICACIONES 1. Material que contiene compuestos quámicos formados entre uno o varios metales (M) del grupo IVA del Sistema Periáodico, nitroágeno (N) y oxágeno (O), caracterizado porque:de un 2 a un 45 % del volumen estaá formado por espacios vacáos, cuyo tamano se situáa en un rango de entre (0,5 nm) 3 y (100 nm) 3 , y el volumen restante presenta una proporciáon de metal del grupo IV A del Sistema Periádico, nitrágeno y oxágeno del tipo 1:(0,1 a 1,7):(0,1 a 1,7), formando un material de foármula MNxOy (siendo X, Y = 0,1-1,7).
- 2Material seguán la reivindicacioán 1, caracterizado porque el volumen restante incluye uno o varios de los compuestos quámicos siguientes:-MNx siendo x = 0,7 a 1,2, -MOx siendo x = 0,7 a 1,2, - Fases Magnelli del sistema M-O (MnO2n-1), -MO2, -M2 N, siendo M = metal del grupo IV A del Sistema Periáodico.
- 3Material seguán la reivindicacioán 1 oá 2,caracterizado porque el metal del grupo IV A del Sistema Periáodico es titanio, circonio o hafnio o una mezcla de dos o tres de dichos metales.
- 4Material seguán una de las reivindicaciones anteriores, caracterizado porque contiene tambien pequenas cantidades de compuestos de carbono del metal.
- 5Material seguán una de las reivindicaciones anteriores, caracterizado porque la parte real del ándice de refraccioán para la longitud de onda de rayos X 0,0709 nm se situáa en el rango de 0,9999984 a 0,9999973 y la densidad máasica del material en el rango de 3,7 a 4,5 g/cm 3 .
- 6Material seguán una de las reivindicaciones anteriores, caracterizado porque el ándice de refracciáon de valor complejo para longitudes de onda del rango de 0,5 a 4,5 μm no indica ni un comportamiento tápicamente metaálico ni un comportamiento tápicamente dieláectrico, y/o la resistencia especáfica de la capa fina se situáa en un rango de 30 a 30.000 μΩ.cm.
- 7Material seguán una de las reivindicaciones anteriores, caracterizado porque se presenta como capa fina, con un espesor de capa situado en un rango de 3 nm a 3 mm, preferentemente de 30 a 120 nm.
- 8Material seguán una de las reivindicaciones anteriores, caracterizado porque la capa fina se aplica sobre un substrato metaálico de geometráa arbitraria tales como molibdeno, plata, oro, cobre, aluminio, volframio, náquel, cromo, circonio, titanio, hafnio, táantalo, niobio, vanadio, hierro o sus aleaciones, recubrieándose la capa fina con por lo menos otra capa fina de uno o varios oáxidos, seleccionados de entre SiO2,ZrO2,HfO2,Al2O3 oY2O3, preferentemente con una capa antirreflexioán de SiO2 de un espesor de 60 a 140 nm.
- 9Aplicaciáon del material seguán una de las reivindicaciones 1 a 8 como absorbente para la conversioán de energáa de radiacioán en energáa táermica, caracterizada porque la combinacioán de capa fina y substrato absorbe determinadas longitudes de onda como absorbente selectivo y la radiacioán irradiada se convierte en energáa táermica.
- 10Aplicacioán seguán la reivindicacioán 9, caracterizada porque en el material la proporciáon de espacios vacáos en volumen es del 20 al 30 %, el espesor de capa es de 40 a 70 nm y como base metaálica se utiliza cobre, molibdeno o aluminio.
- 11Procedimiento para la fabricaciáon de capas finas del material seguán una de las reivindicaciones 1 a 8 por precipitaciáon en vacáo reactiva, caracterizado porque durante la precipitacioán del metal del grupo IV A del Sistema Periáodico, atraváes del mantenimiento de una atmáosfera gaseosa que contiene por lo menos una de las clases de gas N2,O2,CH4 y gases nobles, se forma un compuesto de áoxido, nitruro o carburo y la precipitaciáon de las partáculas de metal sobre un substrato que puede calentarse se controla a traveás de la presioán de gas total Ptot, la velocidad de vaporizaciáon r, la temperatura del substrato Tsub y la distancia entre la fuente metal y el substrato l, situaándose dichos paráametros en los rangos siguientes:T sub = 20 a 400^C, l = 0,01 a 1,5 m, -relaciáon de presiáon parcial de los gases N2 y O2: (PN2/PO2) = 1 a 2.000, -ptot =2x10 -5 hPa - 4x10 -2 hPa y -r=0,01a60nm/s, de modo que se forman capas con una proporciáon en volumen del 2 al 45 % de espacios vacáos, cuyo tamano se situa en un rango de (0,5 nm) 3 a (100 nm) 3 .
- 12Procedimiento seguán la reivindicaciáon 11, caracterizado porque se anaden adicionalmente a la atmáosfera gaseosa H2O y compuestos volaátiles del carbono.
- 13Procedimiento seguán la reivindicacioán 11 áo 12, caracterizado porque en una caámara de recubrimiento al vacáo el metal precipita por vaporizaciáon, sobre un substrato que, por táermino medio, se encuentra a entre 0,01 y 1,5 m del crisol de vaporizaciáon, y a traváes de una o varias vaálvulas de dosificacioán de gas o medidores del flujo gaseoso y la mediciáon y regulaciáon de la presioán parcial con un espectroámetro de masa se mantiene una atmoásfera gaseosa, que contiene por lo menos una de las clases de gas N2,O2,CH4 y gases nobles, ajustando una calefaccioán de substrato, mediante un regulador, la temperatura del substrato en un rango de 20 a 400^C, midiendose la velocidad de vaporizaciáon mediante un cuarzo oscilante y retransmitiendose su senal al vaporizador a traváes de un regulador, y ajustáandose de ES 2 149 342 T3 esta manera la velocidad de vaporizaciíon deseada, de modo que se realizan los paraímetros de recubrimiento descritos en la reivindicaciíon 11, determiníandose adicionalmente la presiíon total de gas mediante un medidor de la presiíon total de gas. NOTA INFORMATIVA:Conforme a la reserva del art. 167.2 del Convenio de Patentes Europeas (CPE) y a la Disposición Transitoria del RD 2424/1986, de 10 de octubre, relativo a la aplicacion del Convenio de Patente Europea, las patentes europeas que designen a España y solicitadas antes del 7-10-1992, no producirán ningún efecto en Espana en la medida en que confieran proteccion a productos químicos y farmaceuticos como tales. Esta informacion no prejuzga que la patente esté o no incluída en la mencionada reserva.
Independent claims13
107 paragraphs in 2 sections, as filed
IS 2 149 342 T3
DESCRIPTION
Material formed by chemical compounds with a metal from group IV A of the periodic system, nitrogen and oxygen, and the procedure for its manufacture.
The present invention refers to a material according to claim 1, as well as to the application of the material according to claim 9 and to a process for the manufacture of the material according to claim 11.
Nitrogen and oxygen titanium compounds cover a wide palette of known material properties and therefore find wide industrial application. Titanium dioxide, for example, is an important component of white wall paint, but it is also used in solar cells. The TiN compound is known as an electrically conductive ceramic and is characterized by its high strength and hardness. This compound is used to harden tools, and in the semiconductor industry it finds application as a diffusion barrier between silicon and aluminum. The mixtures of TiN and titanium ioxide phases are poorly investigated. For practical use, materials that meet both dielectric and metallic properties would be very interesting.
The authors of DE 35 22 427 A1 disclose a material made of titanium and nitrogen, the electrical properties of which are adapted to different applications by the addition of oxygen. This leads to the modification of the chemical composition and negatively influences other physical and chemical properties, such as adhesion, corrosion resistance, temperature resistance or hardness. Especially negative is the fact that this material tends to corrosion when exposed to oxygen. But in addition, when determining the proportion of oxygen the desired properties, these vary with time, which is counterproductive for a practical use.
In the US patent specification by Blickensderfer et al. US 4,098,956 publishes a selective absorbent, coated with TiNxOy. The authors report the proportions of oxygen and carbon present in the coating. Empty spaces are not mentioned as a decisive characteristic nor are they known by the authors as essential properties for the application. The object of US patent 4,098,956 has the drawback that the optical properties of the material can only be adjusted to different requirements by varying the chemical composition. These necessary modifications of the chemical composition cause other necessary properties to be lost, such as adhesion. The authors report on these drawbacks in another publication: R. Blickensderfer, DK Deardorff, RL Lincoln, "Spectral reflectance of TiNx and ZrNx films as selective solar absorbers", Solar Energy, volume 19, pages 429-432, 1977, where problems due to the degradation of these materials are described.
In addition to the many investigations on TiN (see for example DE-OS32 104 20, or DE-OS-33 006 94) and titanium dioxide (see for example DE-OS31 166 77), Vogelzang et al . (E. Vogelzang, J. Sjollema, HJ Boer, J.Th.M. DeHosson, "Optical absortion in TiNxOy compounds", J. Appl. Phys. 61 (9), pg. 4606-4611, 1987) investigated oxynitride titanium (TiNxOy). In the cited work, together with other magnitudes, the complex value dielectric constant e (λ) is published as a function of the wavelength λ in the range of 0.4 to 30 μm. If the degree of reflection and the degree of transmission are calculated with these published values and Fresnel theory, the calculations do not coincide with the results published by the authors in the same work. Therefore it must be assumed that an error has crept into the determination of e (λ). Thus, the explanation of dielectric behavior detailed in this work is not valid either, and therefore its practical transformation is not possible either.
Compounds of titanium, nitrogen, oxygen and carbon are published in the publication DE 36 40 086 A1. As a characteristic, it is required that the proportion of oxygen be higher than that of nitrogen or carbon. But also in this case the proportion of empty space is not entered.
In DE 36 37 810 A1 the manufacture of a material is published, which contains titanium, nitrogen and carbon. It is known that compact layers are formed by the applied ion plating. From this it must be inferred that there are no empty spaces in these layers.
Materials with voids (voids) are often described in the literature, for example for thin TiN layers (see for example PJ Martin, RP Netterfield and WG Sainty, “Optical Properties of TiNx Produced by Reactive Evaporation and Reactive Ion - Beam Sputtering ”, Vacuum volume 32 (1982), pages 359-362 or DE 42 07 368 A1), especially Schellinger et al. on TiNxOy (H. Schellinger, M. Lazarov, H. Klank, R. Sizmann, "Thermal and Chemical Metallic-Dielectric Transitions of TiNxOy-Cu Absorber tandems", Proc. SPIE 2017 "Optical Materials Technology for Energy Efficiency and Solar Energy Conversion XII", 1993 pages 345-356). All the preceding authors report on the mere existence of empty spaces. Up to now, the quantification of these spaces has not been carried out.
The patent specification DE 22 16 432 C3 discloses titanium dioxide with open porosity. The empty spaces that are described in it (pores) have very large volumes.
The optical and electrical properties of the materials can be divided into dielectric and metallic, and the use of the materials is decided according to this division. However, in many applications mixtures of both properties are called for. In an absorber-reflector tandem (see for example DE 26 39 388 C2 or DE 27 34 544 C 2) neither a pure metal nor a pure dielectric can provide a selective absorption for the sun's rays. Semiconductors with and without doping partially fulfill these requirements and are used in many applications. Considering a selective absorbent, the fixed band gap and relatively flat absorption edge typical of a semiconductor are counterproductive to properties.
ES 2 149 342 T3 highly selective properties.
Document DE-OS-35 22 427 refers to the manufacture of electrically conductive temperature and expansion measurement probes, applying layers of titanium oxynitride by reactive ionic vaporization or dusting with high-frequency or DC magnetroan.
Document GB-A-2,186,294 refers to the application of a hard black decoration based on TiOCN, ZrOCN and / or HfOCN by means of electrical deposition on wristwatch straps or spectacle frames.
Document EP-A-0 564 709 refers to a glass substrate on which a laminated system is applied based on a layer of highly refractive material and a layer of low-refractive material. The highly refractive layer of material is made up of hafnium, zirconium, tantalum or titanium oxynitride. The application of the layered system on the substrate is carried out by electrical deposition, which is why compact layers are formed without empty spaces.
US-4,861,669 relates to the fabrication of stacks of IR reflection layers on glass supports by electrical deposition of hard transparent TiON.
JP-A-57-2875 relates to the manufacture of colored layers resistant to abrasion and corrosion based on TiNxOy and TiOzCx Ny as decoration, for example for wristwatches.
JP-A-63-125 658 relates to the decorative coating of watch parts with 0.14 µm Ti-ON compounds. For its part, document JP-A-63-247 350 describes the manufacture of decorative layers based on titanium oxycarbonitride.
The present invention addresses the problem of providing a material that is suitable for a wide field of applications in solar energy and in power plants, but also as a decorative coating for different purposes. For this, the material must possess such properties that they are neither purely metallic nor purely dielectric in nature. Furthermore, the present invention raises the problem of preparing a process with which the material can be manufactured.
The present invention solves the problem by means of the objects of claims 1, 9 and 11. Advantageous developments thereof are the subject of the dependent claims.
The material according to claim 1 contains chemical compounds of one or more metals of group IV A of the Periodic System, nitrogen and oxygen, being formed from 2 to 45%, preferably from 5 to 40%, more preferably than 10 to 28% of the volume by voids, whose size is in the range of (0.5nm)<sup>3</sup> at (100 nm)<sup>3</sup>. The remaining volume of material (from 98 to 55%, preferably from 95 to 60%) has a proportion of metal from group IV A of the Periodic System and nitrogen and / or nitrogen from type 1: (0.1 to 1.7) :( 0 , 1 to 1.7), preferably 1: (0.25 to 1.5) :( 0.25 to 1.5). The material has the formula MNxOy, in which "M" means metal of group IV A of the Periodic System and x and y respectively have values between 0.1 and 1.7.
The above ratios refer to particle number or molar ratios. Regarding the size of the empty spaces, it is preferred that it is located in its lower range, that is, preferably it is not greater than (15 nm)<sup>3</sup>. The "remaining volume" of the material preferably comprises one or more of the chemical compounds selected from MNx (x = between 0.7 and 1.2), MOx (x = between 0.7 and 1.2), Magnelli phases of the MO system (MnO2n-1), MO2, M2N (with M = metal of group IV A of the Periodic System) as well as approximately 0-30%, preferably 0.5-5% of carbon compounds of a metal of the group IV A of the Periodic System. By means of these compounds, preferably additionally included, the spectrum of applications with significant possibilities of use is broadened. Impurities in the form of small amounts of titanium carbides are not disturbing for many properties, but allow cheaper manufacturing. The possibility that the existing chemical phases in the material follow the invention can preferably be in crystalline or amorphous form makes it possible to cover different fields of application, for example in crystalline form as a diffusion barrier in the semiconductor industry, or in amorphous form as a layer. decorative. The metal of group IV A of the Periodic System is titanium, zirconium or hafnium or a mixture of two or three of these metals, preferably titanium.
The material according to the invention can be described in more detail by the fact that when p is the mean value of the mass density of the chemical compounds that make up the material and pm is the mass density of the material including voids, the magnitude p-pm p
it is between 0.02 and 0.5.
Furthermore, it is preferred that the material according to the invention has voids with a fractal size distribution. With the present specification of the void class, the material according to the invention clearly deviates from the materials whose reduced mass density can be attributed to altered lattice constants and high density of defect points. The part of empty spaces defined and their distribution allow to use the material according to the invention as standard in neutron scattering investigations.
The material according to the invention is also characterized in that the real part of the refractive index for an X-ray wavelength of 0.0709 nm is between 0.9999984 and 0.9999973. The mass density of the material according to the invention is preferably 3.7 to 4.5 g / cm<sup>3</sup>, more preferably between 3.8 and 4.2 g / cm<sup>3</sup>. Thanks to these properties, the material according to the invention is also suitable to be used as standard in the density determinations of thin films.
Another property of the material according to the invention is that the refractive index of complex value for wavelengths of 0.5 to 4.5 μm
ES 2 149 342 T3 indicates neither a typical metallic behavior nor a typical dielectric behavior. Therefore, the material is remarkably suitable as a solar radiation converter. The use in the conversion of solar energy into heat requires optical properties in infrared, which are not metallic or dielectric in nature. Metallic properties can be described by Drude's theory, whereas dielectric materials have a very small imaginary part of the refractive index. Electron loss spectroscopic measurements (EELS) show a peak in the material according to the invention, which can be interpreted as a plasmotic wavelength λ<sub>ρ</sub> in the sense of Drude's theory, where λ<sub>ρ</sub> in a value between 1.1 and 0.1 μm. But this plasmotic wavelength does not correspond to the typical metallic behavior (which can be described by Drude's theory) of the ioptic constants.
The material according to the invention is preferably presented as powder or glass. This makes it possible to apply the material in the field of volumetric absorbents.
If mixtures of titanium, zirconium or hafnium compounds are used, the field of application of the material is extended to sectors that require high temperature stability. Zirconium or hafnium compounds show a higher heat stability than titanium compounds and, furthermore, are resistant to diffusion processes.
The material according to the invention can preferably be presented as a thin layer, with a thickness of 3 nm to 3 mm, preferably 10 nm to 2 mm, preferably 30 to 71 nm. Thus, the thin layer preferably exhibits a columnar microstructure. This enables applications where the layer must be porous and rough. The thin layer of the material according to the invention has a specific resistance in a range from 30 to 30,000 μΩ.cm, preferably from 100 to 6,000 μΩ.cm, with total preference from 2,000 to 3,000 μΩ.cm. This property makes available applications in the semiconductor industry that require a different specific resistance in each case but that, for cost reasons, the manufacturing process only has to be slightly modified so that these properties are fulfilled. The specific resistance can be easily adjusted by choosing the proportion of void space. Starting from the specific resistance of the material without empty space, this resistance increases as empty spaces are added. For example, in TiN0.98O0.2 the specific resistance can be 70 μΩ x cm, if the proportion of empty space is 3% and increase to values of 650 μΩ x cm when the proportion of empty space is situated in the 40%.
If additional compounds exist in the material, such as those listed in claims 2 and 4, it is not necessary for them to appear in the same proportion at each depth of the thin layer. In this way, it is possible to apply it as a gradient layer, for example if in selective layers it is desired to vary the optical properties with the layer thickness. This can be done here conveniently by varying the chemical compounds or by modifying the ratio of voids. Preferably the proportion of voids varies with the depth of the thin layer. It is preferred that the top 0 to 50% of the thin layer, measured in total layer thickness, consists of TiO2, ZrO2, or HfO2.
In this way the material is proposed for applications in which the upper layers must have electrical properties, for example in insulators.
The material according to the invention can preferably be applied as a thin layer on a metallic substrate made of molybdenum, silver, gold, copper, aluminum, tungsten, nickel, chromium, zirconium, titanium, hafnium, tiantal, niobium, vanadium, iron and their alloys. The metallic substrate, for its part, can be applied by a coating process on another arbitrary solid support. The metallic substrate is preferably a substrate manufactured by a rolling or casting process, and contains impurities. The material according to the invention formed as a thin layer is preferably applied on a rough substrate surface, the roughness of which is characterized by a statistical distribution of deviations from a mean level, and the standard deviation of this distribution was in a range from 0 to 1,500 nm, preferably 40 to 120 nm. The roughness allows a better absorption at short wavelengths and thus allows the application as an absorber-reflector tandem.
The material according to the invention formed as a thin layer can be coated with at least one other thin layer, composed of one or more ioxides, preferably SiO2, ZrO2, HfO2, Al2O3, Y2O3. With this oxide layer, which preferably has a fineness greater than 60 nm, the material can be passivated, thus increasing its life span. A system of layers of the material according to the invention, with preferably 1 to 45 layers of oxide, can be used as an anti-reflection filter. For this, the ioxides and layer thicknesses of the system are selected by an algorithm, so that the reflection is especially high for a range of wavelengths. The corresponding algorithms can be consulted in the relevant literature (eg T. Eisenhammer, M. Lazarov, N. Leutbacher, U. Schoffel and R. Sizmann, "Optimization of interference filters with genetic algorithms applied to silver-based heat mirrows", Applied Optics, volume 32, 1993). A system of layers of this kind, which is applied on the material according to the invention, can also act by reducing the reflection, allowing a better absorption for certain wavelengths. It is preferred that the sum of the products of the layer thickness of each antireflection layer multiplied by the refractive index (measured in visible wavelength ranges) of the oxide used is between 20 and 180 nm, preferably between 80 and 110 nm.
As already mentioned, with the introduction of the empty spaces a balance can be struck between the different competing properties, for example electrical and metallic properties. In addition to the optical properties, the electrical properties can also be modified accordingly. A resistance is4
ES 2 149 342 T3 specificity of preferably 3,500 µΩ x cm is carried out by means of a proportion of 20 to 25% (% by volume) of voids in the material. Higher specific resistance values can be achieved with a higher proportion of voids. Only the control of the voids allows the controlled variation of the specific resistance and explains the influence of the plasma frequencies on the optic properties. Only this enables a controlled design of the properties of this material, which are then important for certain applications, for example as a selective absorbent.
Materials according to the invention with adjustable properties. which are also stable at temperature and resistant, find applications in different branches of industry:
- In solar energy: If the material according to the invention is applied by a coating procedure with a thickness of preferably 40 to 70 nm, preferably on copper, molybdenum or aluminum, with a proportion of void space preferably from 22 to 26% by volume , a selective absorbent is formed. Said absorber can transform solar radiation into heat at temperatures of 400 ^ C, without it being necessary to concentrate the radiation. In addition, by controlling the chemical composition and the void space ratio, the material properties can be adjusted to obtain an optimal solar radiation performance, depending on the desired temperature of the thermal energy, the meteorology and the concentration. . For use in solar energy, the material is preferably applied in the form of a thin layer on a metal base (metallic substrate) of arbitrary geometry, and the layer thickness is preferably selected in the range of 40 to 80 nm, so that the combination of the thin layer and the metallic base absorbs certain wavelengths as a selective absorber and transforms the irradiated solar radiation into thermal energy. Absorption of wavelengths in the range 0.3 to
1.5 μm. For use in solar energy, the material according to the invention has a void space volume ratio of preferably 20 to 30%, a layer thickness of 40 to 70 nm, and copper or aluminum is preferably used as a metallic base. Even an antireflection layer 70-120 nm, preferably 85-100 nm thick, of SiO2 can additionally be used. In the application of solar energy, the radiation energy is absorbed in the material by heating it, and by means of the coupling of a thermal carrier, the thermal energy is discharged. The thermal carrier can preferably be one or more phases of the water. The absorber can be mounted on an arbitrary solar collector.
- In the semiconductor industry: It is known that silver and gold diffuse through thin layers of TiN. These diffusion quotas are little and badly controllable. By means of the material according to the invention, the diffusion rate can be significantly increased and, at the same time, the electrical properties of the layer are adjusted within a wide range. In particular, a high specific resistance can be selected (preferably 1,000 to 30,000 μΩ x cm). In this way, protected conductors of silver or gold can be manufactured by malleability.
- As a coating for the fins of a radioometer: A thin, thermal insulating sheet, preferably mica or an airgel, is coated with approximately 200 to 1,000 nm of copper, silver or aluminum and then preferably 40 to 150 nm of the material according to the invention. , so that a selective radiation converter is formed, and then this loamine remarkably fits like a fin in a radiometer.
- As a decorative layer: The material according to the invention is preferably suitable as a decorative layer, when the material is applied with a thickness of between 15 and 100 nm on a substrate, preferably with a thickness of 30 to 50 nm, and this combination provides, by an interference effect, a visual impression. The material and the substrate can be coated with a thin layer (approximately 60 to 120 nm), preferably partially transparent.
- In the technology of power plants: The material according to the invention is also suitable as a selective emitter of radiation for the transformation of thermal energy into current, heating the material and releasing thermal radiation as a selective emitter of radiation, said energy being transformed into current by a photocell. In power plants, a layer of a thickness of 50 to 500 nm, preferably of approximately 100 to 200 nm, of the material according to the invention on a substrate (preferably molybdenum) is preferred as the selective emitter, the material containing a proportion of void space of the 7 to 20% by volume. As the material according to the invention is stable at temperature, the emitter can heat up to temperatures higher than 900 ^ C.
- In medicine: The change between dielectric and metallic properties is carried out on a scale of a range of nm. It is known that metals, such as silver, have an antimicrobial action, but at the same time bacteria easily adhere to them and die, forming a film. New germs can be added to this film, which, since they do not have any contact with the metal, do not die. Dielectric materials possess germ-repellent properties. By having the material according to
ES 2 149 342 T3 the invention both antimicrobial (metallic) and germ repellent (dielectric) properties, the bacteria die but do not remain attached. The antimicrobial action is maintained.
This wide field of applications is obtained thanks to the control of the physical properties by means of the empty spaces. This control can be easily foreseen by means of the theory of means effective according to Bruggeman, which considers the material as a mixture of voids and participant phases. An important advantage of the invention is that the desired optical and electrical properties are not only modulated through the chemical composition, but also through the voids. In this way, important properties, such as adhesion, temperature stability, corrosion resistance, etc., which are essentially determined through chemistry, can be preserved.
Other advantages of the present invention are that either the metals of group IV A of the Periodic System, nitrogen and oxygen, and the compounds made with them are not toxic, <sup>Y</sup> or the compounds of titanium, zirconium or hafnium with nitrogen and oxygen are stable at the temperature, resistant (hard) and in comparison with metals like iron or copper they are light.
Furthermore, the problem posed by the present invention is solved by means of a vacuum reactive precipitation procedure (or reactive activated vacuum precipitation) according to claim 11. Following the invention, during the precipitation of the metal of group IV A of the Periodic System on a substrate by maintaining a gaseous atmosphere, which contains at least one of the classes of gas N2, O2, CH4 and / or noble gases, forms an oxide, nitride or carbide compound. The condensation of metal particles on a substrate that can be heated is controlled by the total gas pressure Ptot, the rate of vaporization, r, the temperature of the substrate Tsub and by the distance l between the metal source and the substrate, so that the proportion by volume of voids is from 2 to 45% by volume, and their size was in the range of (0.5 nm)<sup>3</sup> at (100 nm)<sup>3</sup>. The manufacturing parameters are selected as follows:
- T<sub>sub</sub> = 20 to 400 ^ C
- 1 = 0.01 to 1.5 m
- partial pressure ratio of N2 and O2 gases: PN2 / PO2 = 1 to 2,000
-Ptot = 2x10<sup>-5</sup> hPa - 4 x 10<sup>-2</sup> hPa and
- r = 0.01 at 60 nm / s
In the manufacturing process, it is necessary to adjust the manufacturing parameters so that the void part is predictable. This can be done as follows: for substrate temperatures in the range preferably 100 to 220 C and a distance of<sub>5</sub> the source of vaporization to the substrate l of preferably 0.5 to 1.2 m the following applies:
A volume proportion of 34% of empty spaces is reached when:
K = ptot. r / l = (1 to 3) .10<sup>-4</sup> mBar nm sm and the total gas pressure ptot is located between 2 x10<sup>-3</sup> hPa and 2 x 10<sup>-2</sup> hPa.
A volume ratio of% voids is reached when K is selected in the range of:
K = ptot. r / l = (0.2 to 0.5) .10<sup>-4</sup> mBar nm sm
Volume ratios between 20 and 34% can be adjusted by selecting the K quantity according to the following equation:
K = ((0.04 to 0.2). Desired void ratio-0.7). 10<sup>-4</sup> mBar nm sm
In this way it is possible to achieve the desired proportion of empty space in the material according to the invention, with the quota r, with the total pressure ptot and with the distance 1.
Similarly, for substrate temperatures preferably between 250 and 400 ° C and preferably between 0.5 and 1.2 m, the volume ratio of voids in the layer can be controlled as follows:
A volume ratio of, for example, 40% empty spaces is reached when:
K = (6a8) .10<sup>-4</sup> mBar nm sm and the total gas pressure ptot is located between 2 x 10<sup>-2</sup> hPay4x10<sup>-2</sup> hPa. When K is selected in the range of:
K = (0.8 to 1.9).
<sub>10</sub> - 4 mBar nm sm a volume proportion of 20% of voids is reached. To make values between 20 and 40% by volume, K must be selected according to the following equation:
K = ((0.12 to 0.31). Desired void ratio-0.4). 10<sup>-4</sup> mBar nm sm
The intermediate volume ratios can be determined respectively by linear interpolation. Small void volume ratios (2 to 20%) are achieved at low velocities of 0.01 to 0.1 nm / s and low gas pressures of 10<sup>-4</sup> a2x10<sup>-4</sup> mBar. With high total gas pressures of> 4x10<sup>-2</sup>
ES 2 149 342 T3 mBar very large proportions of void space (> 40%) are reached. At these gas pressures the material can appear as a porous compound. According to the invention, the layer is applied on a substrate preferably made of molybdenum, silver, gold, copper, aluminum, tungsten, nickel, chromium, zirconium, titanium, hafnium, tautum, niobium, vanadium, iron or their alloys. To manufacture the material as a block without a base, there are two suitable methods:
- Precipitation (PVD) is carried out on NaCl, KBr or other salts with an arbitrary thickness. The salt is then dissolved in water and the material according to the invention remains as a residue.
- Precipitation is carried out on fine metals with a low melting point, such as copper, aluminum, tin, zinc or brass. Then the material and the substrate (base) are heated in a high vacuum (10<sup>-10</sup>), at temperatures close to the melting point of the metal, so that the metallic base vaporizes. The remaining material is the material according to the invention.
The layer thickness is arbitrary, preferably 30 to 120 nanometers. Preferably, the gaseous atmosphere can also contain H2O and volatile carbon compounds. In this way the manufacturing process can be cheaper. In some cases it may be considered to totally replace the oxygen with water, or to let in air.
In the procedure according to the invention, a metal of group IV A of the Periodic System is precipitated in a vacuum coating chamber by means of vaporization, on a substrate that, on average, is between 0.01 and 1.5 m from the crucible. vaporization. A gaseous atmosphere is maintained through one or more gas dosing valves or gaseous flow meters and the measurement and regulation of the partial pressure with a mass spectroometer. The gaseous atmosphere contains at least one of the classes of gas N2, O2, CH4, and noble gases. By heating the substrate, the temperature of the substrate is adjusted in a range of 20 to 400 ^ C, by means of a regulator, preferably a PiD regulator. The vaporization speed is measured through an oscillating quartz, whose signal controls through a regulator, preferably a PiD regulator, the performance of the vaporizer. Set the desired vaporization speed. The above-mentioned coating parameters are made with the device. In addition, a total gas pressure meter determines the total gas pressure. For the vaporization an electron beam vaporizer and / or a resistance vaporizer and / or an induction vaporizer is used. Using a resistance or induction vaporizer the device according to the invention is cheaper. The substrate is preferably heated by radiation heating and regulated to the required substrate temperature of 20 to 400 ° C. Induction or electric resistance heating is also suitable.
The vaporization of the metal is preferably carried out in a separately evacuable chamber, and this chamber is joined by a diaphragm with a chamber containing the gaseous atmosphere and the substrate, so that the vaporized metal reaches the substrate through said diaphragm. This way of execution allows a higher total pressure without affecting the life of the vaporizer.
The gaseous atmosphere mixture is preferably monitored through separate gas flow meters or by a mass spectroometer. For measuring the magnitude ptot, for example, a damping vacuum gauge or a baratron is suitable. With the device according to the invention, gradient layers must also be produced. In these layers the composition varies with the layer thickness, which can be controlled by the composition of the feed gases. With an increase in N2, layers containing more nitrogen are obtained. The composition of the gas can be regulated by means of the inflow or the measurement of the partial pressure. If a damping vacuum gauge is used, reproducible layer properties can be produced with the device according to the invention.
If the substrate is a tape or a lamina, formed according to the characteristic cos<sup>n</sup> (where n = 1 to 7) of the vaporizer, so that said tape or sheet respectively adapts to the vaporizer characteristic of the vaporizer, a uniform coating of the entire surface is guaranteed.
Preferably, the coating chamber is connected to one or more other coating chambers through a vacuum passage that can be evacuated separately, and the substrate is led from one chamber to the other without breaking the vacuum, being subjected in each of chambers to a separate coating process and thus manufacturing multilayer systems.
The invention is described below by means of Figures 1 to 9.
Figure 1 shows the imaginary part of the refractive ondx at 10 µm as a function of the void space ratio for TiNxOy (crosses) and ZrNxOy (tri-angles) [where x = 0.7 - 0.9; y = 0.3-0.6].
Figure 2 shows the degree of solar absorption of a 55 nm thick TiNxOy-Cu absorber as a function of the proportion of void space [where x = 0.7 - 0.9; y = 0.3 0.6].
Figure 3 shows the degree of toxic emission at 250 ^ C of a TiN absorbent.<sub>x</sub>OR<sub>Y</sub>-Cu 55 nm thick as a function of the proportion of empty space [where x = 0.7 0.9; y = 0.3-0.6].
Figure 4 shows the elemental composition referred to titanium as a function of the partial pressure of oxygen in the layer in TiNxOy [where x = 0.7 - 0.9; y = 0.3-0.6].
Figure 5 shows the ratios of the layer mass density and the volume density as a function of the proportion of void space in
IS 2 the TiN<sub>x</sub>OR<sub>Y</sub> (crosses) and ZrN<sub>x</sub> OR<sub>Y</sub> (triangles)
[where x = 0.7-0.9; y = 0.3-0.6].
Figure 6 shows the real part of the Refractive Index as a function of wavelength with different proportions of void space in TiNxOy layers [where x = 0.7 - 0.9; y = 0.3-0.6].
Figure 7 shows the imaginary part of the refractive onyx as a function of wavelength with different proportions of void space in TiNxOy layers [where x = 0.7 0.9; y = 0.3-0.6].
Figure 8 shows a section through a selective solar absorber in which the material according to the invention has been used.
Figure 9 shows a section through the manufacturing device.
Example 1
In a high-vacuum installation, titanium and zirconium were vaporized by means of an electron beam vaporizer in a gaseous mixture of nitrogen and oxygen. The partial pressure of the nitrogen was from 2.5 to 9.5x10<sup>-4</sup> mBar and that of oxygen varied in a range of 1 x 10<sup>-8</sup> mBary8x10<sup>-5</sup> mBar. 2 mm thick copper discs and 1 mm thick glass discs were vaporized. During the process these substrates were maintained at 170<sup>°</sup>C. On a flat electrode, a plasma discharge was ignited in the container. This increased the disposition to the formation of TiN and TiO and of ZrN and ZrO respectively in the layer. Samples of different layer thicknesses (30 to 120 nanometers) and void space ratios (5 to 32% by volume) were manufactured for analysis. The partial pressure ratio of N2 to O2 was kept at 35, and the distance from the substrate to the vaporizer was 0.8 m. The proportion of voids was controlled by the vaporization rate, which adopted the following values: 0.06 nm / s for low proportions of voids and up to 0.2 nm / s for high proportions of voids.
The crystalline phases of TiN and TiO and of ZrN and ZrO respectively were identified by X-ray reflectometry. The elemental composition was measured by Elastic Record Detection (ERD). Layer thickness and density were determined by Grazing Incidents X-Ray Reflectometry (GIXR). The proportion of voids and their size distribution were determined by measuring the scattered X-ray radiation under grazing incidence.
It was found that the mine density of the layer decreased with respect to the density of compact TiO or TiN in the proportion in which it was filled with voids. Deviations from this norm of 3 to 5% were found for zirconium. The degree of solar absorption at<sub>Sun</sub> It was determined from measurements of the directional hemispheric reflection degree ρ (λ) following ~ / θ °° ΛΜ15 (λ) (1-ρ (λ)) ύλ <sup>aso1</sup> = / θ ° ΛΜ15 (λ) άλ
342 T3 14 where ΛΜ 15 (λ) is the standard solar spectrum ΛΜ
1.5 and lamda the wavelength of the radiation. The degree of heat emission was measured calorimetrically at temperatures of 150 to 400<sup>°</sup>C. The ioptic constants were determined from measurements of reflection and transmission by the generally known graphical method.
The results are represented in Figures 1 to 7. Said figures are described below in greater detail.
Figure 1 shows the imaginary part of the refractive index at 10 µm as a function of the void space ratio for TiNxOy (crosses) and ZrNxOy (triangles). The imaginary part without empty spaces is elevated, a typically metallic property. A proportion of 20% to 25% of voids produces a mixture between metal and dielectric behavior. In both examples it appears that a proportion of 20 to 30% allows a decrease in the imaginary part of the refractive index to be achieved at moderate values. In applications as a selective solar absorber, this means that the degree of heat emission can be kept low. The refractive index can be determined ellipsometrically or by measuring the degree of reflection and transmission. The proportion of voids and their size were measured by X-ray scattering and neutron scattering respectively.
Figure 2 shows the degree of solar absorption of a 55 nanometer thick TiNxOy-Cu absorber as a function of the proportion of void space. Measuring the degree of spectral reflection of the absorber and joining it with the spectrum of solar irradiation on the earth, the proportion of absorbed energy, the degree of solar absorption, was determined. A material with a void ratio of 27.5% produces a maximum degree of absorption.
Figure 3 shows the degree of heat emission at 250<sup>°</sup>C of a 55 nm thick TiNxOy-Cu absorbent as a function of the proportion of void space. The degree of heat emission decreases as the proportion of void space increases, which can be explained by the reduction of metallic properties. To measure the degree of heat emission, the sample must be placed under vacuum at the measurement temperature, which in the present example is 250<sup>°</sup>C. By means of a suitable disposition it is obtained that the sample only loses heat by radiation. The degree of emission was calculated from the energy balance.
Figure 4 shows the elemental composition based on titanium as a function of the partial pressure of oxygen in the TiNxOy layer. The nitrogen to oxygen ratio was controlled in a range of 1 to 2,000 in the device according to the invention for the manufacture of the material according to the invention. In this way, the chemical properties required for applications as a selective absorber in solar energy were achieved, such as, for example, high adhesion achieved with a low partial pressure of oxygen.
Figure 5 shows the ratios between layer miasic density and volume density as a function of the proportion of void space in TiNxOy (crosses) and ZrNxOy (triangles). It can be seen that the bulk density is controlled by the
ES 2 149 342 T3 void space ratio.
Figure 6 shows the real part of the refractive index as a function of wavelength with different proportions of void space in TiNxOy layers. With a void space ratio of 18% by volume, the true part of the refractive index still shows metallic properties and increases with wavelength. At a proportion of 22% by volume, neither the metallic nor the dielectric properties dominate, and at 32% by volume the material is essentially dielectric.
Figure 7 shows the imaginary part of the refractive index as a function of wavelength with different proportions of void space in TiNxOy layers. With a void space ratio of 18% by volume, the imaginary part of the refractive index still shows metallic properties and increases with wavelength. At 22% by volume, neither metalic nor dielectric properties dominate, and at 32% by volume the material is dielectric over wide wavelength ranges.
Figure 8 shows an application of the material according to the invention. Said figure represents a section through a selective solar absorber in which the material according to the invention (2) has been used. On a highly reflective substrate (1), copper, a 55 nanometer thick layer of the material has been applied according to the invention (2), and said layer has been coated in turn with a 92 nanometer thick anti-reflection layer of SiO2 (3). With the antireflection layer the degree of solar absorption is increased from 0.8 to 0.94. In the case of the material according to the invention (2), it is a material characterized by a void space ratio of 27.5% by volume and a titanium: nitrogen: oxygen ratio of 1: 0.92: 0.35 .
Figure 9 shows a section through a device for carrying out the manufacturing process according to the invention. A copper tape (2) is led over an electron beam vaporizer (1). Said tape is kept in a curved shape by rollers (3), so that the coating is uniform. The curvature follows the characteristic of the vaporizer, which may differ from that of a Lambert radiator. While the characteristic of a Lambert radiator can be described by the “Law of the cosine<sup>1</sup>”, In an electroinic beam vaporizer a modification of said law must be taken into account, that is, a“ cosine<sup>n</sup> ”, N being in a range from 1 to 7.
Contents2
9 sheets
Sheet 1 Sheet 2 Sheet 3 Sheet 4 Sheet 5 Sheet 6 Sheet 7 Sheet 8 Sheet 9
16 members in 11 offices
Priority claims4
| Document | Office | Kind | Date |
|---|---|---|---|
| 19934344258 | Germany | – | |
| 4344258 | Germany | A | |
| 1994EP04213 | World Intellectual Property Organization (WIPO) | – | |
| 9404213 | European Patent Office (EPO) | W |
Members16
| Document | Office | Kind | |
|---|---|---|---|
| WO9517533A1 | World Intellectual Property Organization (WIPO) | A1 | |
| AU1383795A | Australia | A | |
| DE4344258C1 | Germany | C1 | |
| EP0736109A1 | European Patent Office (EPO) | A1 | |
| CN1138353A | China | A | |
| JPH09507095A | Japan | A | |
| US5670248A | United States of America | A | |
| US5776556A | United States of America | A | |
| EP0736109B1 | European Patent Office (EPO) | B1 | |
| AT194395T | Austria | T | |
| ATE194395T1 | Austria | T1 | |
| DK0736109T3 | Denmark | T3 | |
| ES2149342T3This record | Spain | T3 | |
| GR3034501T3 | Greece | T3 | |
| CN1070933C | China | C | |
| JP3524552B2 | Japan | B2 |
1 legal event, as the office reported them to INPADOC
Events
| Event | Code | |
|---|---|---|
| Definitive protectionFG2A | FG2A |
Numbers
- Publication
- 2149342
- Application
- 95905080
Titles2
- Spanish
- MATERIAL FORMADO POR COMPUESTOS QUIMICOS CON UN METAL DEL GRUPO IV A DEL SISTEMA PERIODICO, NITROGENO Y OXIGENO, Y PROCEDIMIENTO PARA SU FABRICACION.
- English
- MATERIAL FORMED BY CHEMICAL COMPOUNDS WITH A METAL FROM GROUP IV A OF THE PERIODIC SYSTEM, NITROGEN AND OXYGEN, AND PROCEDURE FOR ITS MANUFACTURE.
Classification
- CPC, 14
- F24S70/225
- C01B21/0821
- C01P2006/40
- C23C14/0676
- G02B1/10
- Y02E10/40
- F24S70/25
- H10P14/69391
- H10P14/69395
- H10P14/69396
- H10P14/69392
- H10P14/69215
- H10P14/6334
- G02B1/11
- IPC, 9
- C23C14 08
- C01B21 082
- C01G23 00
- C01G25 00
- C23C14 06
- C23C14 24
- F24J2 48
- G02B1 10
- H10P14 69