ES2622461B1 - Thin layer deposition procedure of controlled stoichiometry on substrates by flush-angle reactive sputtering - Google Patents

Abstract

Method of deposition of thin layers of controlled stoichiometry on substrates by reactive sputtering sputtering. # The object of the invention relates to a procedure for the deposition of thin layers on a substrate, based on the technique of reactive sputtering, with The objective is to control the chemical composition of the deposited material and, in parallel, to increase the deposition rate with respect to what would be obtained by this procedure in its conventional mode of use. # It is possible to avoid cathode poisoning by determining the critical value of reactive gas flow in the reactor from which said phenomenon occurs and arranging the substrate in a geometric configuration with respect to the cathode so that the pulverized species thereof reach the surface of the substrate according to an average flush angle, measured with respect to this, with values between 0º and 85º.

Description

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Thin layer deposition procedure of controlled stoichiometry on substrates by flush-angle reactive sputtering

DESCRIPTION

SECTOR AND OBJECT OF THE INVENTION

The invention is part of the field of materials science and technology and, more specifically, in the field of surface treatment with layers deposited on them.

Specifically, the invention relates to a process for the deposition of thin layers on a substrate, based on the technique of reactive sputtering, with the aim of controlling the chemical composition of the deposited material and, in parallel, increasing the deposition rate with respect to which would be obtained by this procedure in its conventional mode of use. The claimed process can be used to deposit a wide range of materials and has an industrial scale application.

STATE OF THE TECHNIQUE

Magnetron or "magnetron sputtering" (MS) sputtering is a thin-layer physical deposition technique widely used in the industry for high value-added applications, both for coating small surfaces, for example, in optics, electronics and other applications nanotechnological, such as for large surfaces, such as architectural glass or solar panels.This technique uses a blank or cathode as a source of the material to be deposited that is exposed to a plasma of an inert gas, preferably Ar, under reduced pressure and developing the process without the need to heat said target or cathode externally.This plasma pulverizes it, emitting species with energies in the range of 10 eV, preferably in the direction perpendicular to its surface.These species pass through the plasma, experiencing a variable number of processes of dispersive interaction with the atoms and molecules of plasma gas at before reaching a surface or substrate where they are deposited in the form of a thin film.

A particular way of working is the so-called "reagent", very useful for preparing layers of oxides, nitrides or other compounds from targets of a metallic element. This way of working is compatible with modes of operation in which the target is excites by applying potential DC, pulsed DC or radio frequencies.

"reactive" work, in addition to a noble gas (typically Ar), a small

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quantity of reactive gases in the plasma (for example, oxygen and / or nitrogen gas), which results in an alteration of the chemical composition of the film and, therefore, of its stoichiometry. This is the usual procedure in the case of the synthesis of layers of oxides, such as SiO2 or TiO2 from targets or metal Ti and Si cathodes and a plasma containing a mixture of Ar + O2.

Similarly, in the case of nitrides such as AlN or Si3N4, nitrogen is added to the Ar to achieve the desired composition from Al or Si targets. Other types of compounds such as carbides, oxynitrides, etc. They can be prepared using this methodology. They can be of a single metallic element or of several, using in this case alloy targets, homogeneous or heterogeneous metal mixtures, as well as compounds. Thus, by adjusting the amount of reactive gas in the plasma, fully or partially nitrated or oxidized films can be prepared, for example, TiO2, SiO2, AlN or, alternatively, TiOx, SiOx or AlNx where x is less than the corresponding value in the completely stoichiometric oxide or nitride.

However, the control of the stoichiometry of the layer, that is to say the value of xo, which is the same as the ratio O / M or N / M, where M is the metallic element, is achieved by adjusting the partial pressure of the reactive gas in the plasma, which produces unwanted phenomena of cathode poisoning, that is, changes in surface composition due to the reaction with said reactive gases. These phenomena are revealed in the so-called hysteresis curves, whose generic representation is shown in Figure 1. The specific curves for each particular situation depend on the experimental conditions used: electromagnetic power to maintain the plasma, inert gas pressure, composition , size and design of the target, relative distance between the target and the substrate, geometry of the reactor and the pumping speed of the vacuum pumps, and are obtained by progressively increasing the flow of reactive gas in the reactor. In the case of the growth of an oxide, working with electrical signals DC, pulsed DC or radiofrequency, the different stages or sections of said curve are illustrated in Figure 1. The considerations would be analogous in the case of nitrides, oxynitrides, carbides or other composite materials, being in this case the reactive gases nitrogen or combination of oxygen and nitrogen or other gases.

A series of sections defined by the reactive gas flow range, its increase or decrease and the resulting partial pressure are differentiated in this curve.

• Section A: For low oxygen flows, the target barely oxidizes, since the plasma manages to pulverize the little oxygen that has been incorporated into its surface. In

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Consequently, the blank or cathode functions as if there is no reactive gas in the reactor and the oxygen species are incorporated into the thin film. In this situation, the deposition rates are high, as corresponds to a process from a metal cathode. This phase is known as metallic mode, where the films grow incorporating a low proportion of reactive species.

• Section B: the range of reactive gas flows (in this illustration oxygen) have intermediate values and the partial pressure is still mostly low. The cathode continues in metallic mode until the partial pressure of oxygen in the reactor is high enough to begin to oxidize it, its effective composition altering resulting in the outermost layers oxidizing (or nitriding if nitrogen was used as a reactive gas) . The formation of this oxide (nitride) layer gives rise to different non-linear phenomena that reinforce each other, among which the following stand out: i) the rate of pulverization of metallic species decreases with increasing the amount of oxygen or reactive element incorporated into the target surface, and ii) the conductivity of the cathode decreases significantly, since its surface is formed by an insulating oxide layer, altering the plasma and further decreasing the spray rate. As a consequence of all this, the partial pressure of oxygen in the chamber increases rapidly, a fact that is manifested graphically by the jump in pressure when the reactive gas flow rises slightly. The critical reactive gas flow value Oc is determined by this point. This jump represents the transition from the metallic mode to the so-called reactive mode of the cathode, and is characterized by the growth of thin films with a high proportion of atoms of reactive species, although not reaching the completely stoichiometric composition, that is, stoichiometry type is obtained. MOx where, for TiOx or SiOx cases, the value of x would be less than two.

• Section C: as the flow of reactive gas continues to increase, the target or cathode oxidizes further and the partial pressure of oxygen increases with the flow of oxygen. This phase is known as reactive or "poisoned" mode. The deposition rate decreases dramatically, layers with high oxygen proportions with respect to the metal are obtained, the stoichiometric composition being generally achieved.

• Section D: in the descending phase the flow of oxygen decreases, the cathode is still oxidized, the value of the partial pressure of oxygen in the chamber being similar to that of the previous case. White works under typical conditions in a reactive manner, and the films continue to grow with a completely stoichiometric composition and at very low growth rates.

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• Section E: by decreasing the oxygen flow further, the cathode is still oxidized, even for reactive gas flow values below Oc for those in the initial ascending phase, which operated in the metallic mode. In this section, the target is still completely oxidized (or nitride), the deposition rate is still very low and the deposited material is completely stoichiometric.

• Section F: when the flow of oxygen, or reactive gas, is sufficiently low, the target returns to the metallic mode, reproducing what happened in section A.

Cathode poisoning in reactive cathodic spraying has been known for decades, with great effort being devoted to reducing or eliminating problems associated with this phenomenon, in particular,

i) the low efficiency of the process by reducing the deposition rate in the reactive part of section B, C, D and E, and

ii) the lack of stability and control of the process in the transition between the metallic mode and the reagent, which causes a small fluctuation of the gas flows in the reactor to strongly alter the stoichiometry of the film, with the consequent variation of the deposition rate

The most relevant procedures to avoid this problem are based on:

• Increased pumping speed [Danroc J. et al. "Reactive magnetron sputtering of TiN: Analysis of the deposition process". Surface and Coatings Technology, Volume 33, 1 (1987); Spencer AG et al. "Pressure stability in reactive magnetron sputtering", Thin Solid Films, Volume 158, (1988 )] in the vacuum chamber, so that the consumption of reactive gas by the pumping system dominates the growth of the layer.The main problem of this procedure, particularly in the industry, is the increase in costs of a system pumping adapted for large vacuum chambers.

• Increase the white-to-substrate distance [Schiller S. et al. “Reactive high rate D.C. sputtering: Deposition rate, stoichiometry and features of TiOx and TiNx films with respect to the target mode ”; Thin Solid Films, Volume 111, (1984)]. By making this distance greater, the deposition rate of the pulverized cathode material can be modulated and its composition controlled. However, from an industrial efficiency point of view, this approach is not practical since it reduces the deposition rate and involves working with even larger vacuum chambers, with the consequent increase in costs.

• Selective obstruction of the flow of reactive gas to the cathode [Maniv S. et al. “High rate deposition of transparent conducting films by modified reactive planar magnetron sputtering of Cd2Sn alloy’; Journal of Vacuum Science and Technology 04; 18 (2-18), (1981); Scherer

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M. et al., “Reactive high rate d.c. sputtering of oxides ’’, Thin Solid Films 119, (1984)], introducing a slit or deflector between the cathode and the substrate that facilitates the entry of the reactive gas into the system right next to the substrate. In this way it is possible to deposit layers of high stoichiometry before the cathode is completely poisoned. On the contrary, this procedure requires frequent cleaning of the slit or reflector, also producing a reduction of the metallic flow to the substrate.

• Press the flow of reactive gas [Aronson A.J. et al. “Preparation of titanium nitride by a pulsed d.c. magnetron reactive deposition techniques using the moving mode of depositionThin Solid Films 72 (1980); US4428811; US4428812; Sproul W.D. et al. “High rate reactive sputtering process control’, Surface Coatings Technol. 33 (1987)] to operate in metallic mode stably. This is achieved by activating and deactivating periodically and in short intervals the flow of the reactive gas using a piezoelectric valve. The interval where the flow of reactive gas is deactivated allows the elimination of compounds formed on the cathode surface before they accumulate causing their poisoning. The main disadvantages of this technique are associated with the need for extensive process optimization work prior to the deposition of layers with the required stoichiometry, and the need to continuously review and adjust its parameters.

• Use stability control systems based on plasma emission monitoring (PEM) [J. Musil et al. ’’ Reactive magnetron sputtering of thin films: present status and trends ”; Thin Solid Films 475 (2005) 208-218] to be able to automatically control the pressure and thus be able to work in the transition zone between metallic and reactive mode. These control systems become unstable for high reactive gas flows.

EXPLANATION OF THE INVENTION

The object of the present invention is a method of deposition of thin layers of stoichiometry controlled on substrates by sputtering angle reactive sputtering comprising the following steps:

- placing the substrate on which the deposition of the thin layer in the reactor that contains a blank that acts as a cathode, which provides material to deposit, will occur.

- application of an electromagnetic power that induces an average cathode voltage between 50 V and 10 kV in the presence of a mixture of inert and reactive gases a

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a total pressure between 10-2 Pa and 10 Pa where the contribution of the reactive gas is between 0.1% and 50%.

- ignition of a plasma that pulverizes the cathode emitting species that leave it with energies between 10-2 eV and 100 eV.

- deposition of said species, together with others from the reactive gas, in the form of a thin layer on the substrate

- determination of the critical value of reactive gas flow in the reactor from which cathode poisoning occurs resulting in a variation greater than 5% of the total pressure in the reactor and a decrease in deposition rate greater than 50% . The flow of reactive gas in the reactor is selected to be between 0% and 99% of its previously determined critical value, and the substrate is arranged in a geometric configuration with respect to the cathode, so that the species sprayed from it they reach the surface of the substrate according to an average flush angle measured with respect to it with values between 0 ° and 85 °.

The electromagnetic power is applied by a source that operates in DC, pulsed DC or radiofrequency.

The materials for the substrate are selected from metals, stainless steel, polymers, silicon and other semiconductors, sapphire, glass or quartz or similar compounds.

The materials to be deposited are selected from Ti, Si, Al, Cr, V, Zr, other metals, as well as mixtures thereof and alloys.

The inert gas is selected from Ar, He, Kr or combinations thereof and the reactive gas is selected from O2, N2, hydrocarbons or combinations thereof.

In operation, the average flush angle with which the pulverized species reach the surface of the substrate is preferably between 0.1 ° and 45 °.

BRIEF DESCRIPTION OF THE FIGURES

Figure 1: Scheme of a generic hysteresis curve showing the pressure variation in a reactive sputtenng magnetron reactor when the reactive gas flow is changed, in this case oxygen. The different typical sections of the hysteresis process are indicated.

Figure 2: Value of v that defines the limit of L / Á (where L is the white-substrate distance and Á the mean free path of the species within the plasma / gas) as a function of the ratio between the mass of the plasma species, Mg, and the powdered cathode, Ms.

Figure 3: Hysteresis cycle for deposition by reactive magnetron sputtenng of titanium oxides (3a) and silicon oxides (3b) in the classical normal configuration (substrate parallel to

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White). The value of the ratio between oxygen and metal for the different O2 flows is indicated in each case. The experimental conditions in the case of TiOx are: Electromagnetic power 300 W (DC), argon partial pressure: 0.2 Pa, white-film distance: 7 cm, angle of inclination of the substrate: 0 °. In the case of SiOx they are: electromagnetic power 200 W (pulsed DC, 80 kHz, “off” time 5 ^ s), argon partial pressure: 0.2 Pa, white-film distance: 7 cm, substrate inclination angle : 0 °.

Figure 4: Change of the oxygen / metal ratio in the case of the growth of TiOx (4a) and SiOx (4b) by varying the angle of the substrate with respect to the target for an oxygen flow of 2 sccm (cubic centimeters per minute in units standard, scm3.min-1), less than the critical flow in each case (measurements made by Rutherford backscatter spectroscopy). Additional experimental conditions in the case of TiOx are: Electromagnetic power 300 W (DC), argon partial pressure: 0.2 Pa, white-film distance: 7 cm. In the case of SiOx they are: electromagnetic power 200 W (pulsed DC, 80 KHz, “off” time 5 ^ s), argon partial pressure: 0.2 Pa, white-film distance: 7 cm. Figure 5: Growth rate in the cases of depositing TiO2 and SiO2 using the conventional method in normal geometry and the one proposed in this invention to flush geometry (measurements performed by Rutherford backscatter spectroscopy). In both cases, an increase of the rate approximately four times greater is obtained. The experimental growth conditions in each case are detailed in Table I. Figure 6: Scanning electron microscopy images in cross-section of layers of SiO2 (6a) and TiO2 (6b) prepared by magnetron sputtenng at flush angle (mean incidence of 17 ° with respect to the surface of the substrate) controlling the proportion of oxygen so that the process takes place in the metal deposition mode.

DETAILED DESCRIPTION OF THE INVENTION

The present invention proposes a new method based on the use of flush or oblique angle deposition geometries ("oblique angle deposition", OAD), also called "glancing angle deposition (GLAD)", in which the species that are emitted from the white are made to incline at flush angles on the substrate. This possibility can be achieved by changing the position and / or orientation of the substrate with respect to the cathode surface, for example by rotating one with respect to the other. Through this technique it is possible to control with great precision and reproducibility the O / M atomic ratio in the case of oxides, or N / M in the case of nitrides (M metal element), so that both layers can be achieved

Sub-stoichiometric as completely stoichiometric using reactive gas flows

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low or intermediate, this is operating the system in the cathode metal mode. In this way, higher deposition rates are achieved than those that would be obtained by the traditional procedure in a non-flush geometry and raising the flow of reactive gas until reaching high proportions of reactive species in the film, and thus promoting cathode poisoning. The process object of the invention is much more precise and reproducible than other alternative methods, presenting the additional advantage of optimizing the deposition rate and avoiding hysteresis phenomena that restrict the use of the reactive sputtenng magnetron technique.

The process object of the invention allows to control the stoichiometry of thin layers on substrates at high deposition rates using the technique of reactive sputtering in a working mode in which cathode poisoning is avoided. The deposition procedure is based on the control of two parameters that are fundamental in the process:

i) the angle of incidence of the cathode or blank particles on the substrate (a), and

ii) the partial pressure of the gases in the reactor (p), through direct control of the gas inlet flows and pumping speed.

The value of this last magnitude is directly related to the total pressure in the system that regulates the mean free path of the species extracted from the cathode by means of sputtering (Á), this parameter being understood as the average distance that these species travel within the plasma / gas without suffering any collisional dispersion process. The value of the mean free path decreases with the gas pressure in the chamber, so that the magnitude that really controls the process is the ratio L / Á, where L is the distance between white and substrate that is usually a constant for a specific reactor dice. The pressure conditions that are applied in the present invention are those for which the value of L / Á does not exceed the value of v, (number of average collisions required for the cathode species to become totally thermally and lose their preferred direction) given in Figure 2, dependent on the mass of the cathode sprayed species and the mass of the species that make up the plasma. This condition ensures that, mostly, the species that leave the cathode maintain the original direction when they reach the substrate

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The fundamental idea on which the invention is based lies in modulating the deposition rate of species sprayed from the cathode by varying the angle of arrival of the target species on the film being grown. This idea is based on the high directionality of the pulverized material when it is emitted from the target, preferably perpendicular to its surface and with a kinetic energy in the range of 10 eV. Thus, by tilting the film with respect to the target or using any other strategy that allows varying the angle of incidence of the species sprayed from the target on the substrate, working under pressure conditions where L / A <u, the surface area factor (cosine factor), modulating the deposition rate of pulverized cathode material, while the probability of arrival of species that have a more isotropic distribution of velocities, such as reactive species in plasma, is not It is affected. The control of the pressure of the gases in the reactor allows to vary the mean free path A of the target species sprayed and, therefore, the number of collisions they experience before being deposited. In particular, collisions with heavy plasma species cause the decrease in kinetic energy of the sprayed species to typically thermal values (of the order of 0.01 eV), as well as the randomization of their velocities. Therefore, the control of the pressure of the gases in the plasma allows to control the fraction of pulverized species that arrive with high directionality and whose deposition rate can be modulated by tilting the film or positioning the substrate in a flush arrangement with respect to the species pulverized

The mathematical equation that describes the variation of the stoichiometry of a material with MOx or MNx composition, by varying the angle between the target and the film a and, therefore, the angle of incidence of the target species on the substrate, is the next:

X0 = PXa,

where x0 is the stoichiometry in the classical configuration (white and parallel film), xa the stoichiometry obtained by rotating the film an angle a, and f3 a function always smaller than 1, dependent on the pressure in the reactor p, white / film distance L, nature

of the gases and angle of incidence of the species on the substrate. In the case of the deposition of silicon oxides, f3, it turns out to be

exP (E) -1

(1 - thing),

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where S = 17.2pgL (Pa-1m-1), with pg the pressure of the gases in the reactor and L the

distance between the white and the film. Thus, for low pressures the ratio xa = x0 / thing is obtained, that is, a large variation of stoichiometry with the angle of incidence of the target species, while at high pressures it is found that xa = x, ie ., no variation is obtained with pressure because of the high number of

Collisions between the pulverized material and heavy plasma particles eliminates directional flows.

The invention proposes to operate the deposition in the metallic zone of section B of the hysteresis curve (figure 1), where high deposition rates and small values of x0 are obtained.

Thus, tilting the film allows the growth of films with high or fully stoichiometric stoichiometry and at higher deposition rates than by the classical procedure operating in regions C, D and E (Figure 1). In addition, by always working on the metal part of section B, possible plasma instabilities and hysteresis phenomena are avoided, so that deposition is more stable, controllable and reproducible. An additional feature of the layers prepared by the proposed methodology is their high structuring with microstructures formed by well-defined nanocolumns and relatively low density, ideal for certain applications where, for example, it is interesting to control the optical properties of the layers. This special microstructure is the result of the oblique configuration during deposition that favors the effects of "shadow" during the growth of the layers.

MODE OF EMBODIMENT OF THE INVENTION

The procedure includes:

1. - Prior characterization of the working mode of the target or cathode by obtaining its characteristic hysteresis curve in the reactor used, setting the conditions of distance from the substrate to the target for an angle of incidence of the particles of 90 ° (inclination of the zero substrate) and a given electromagnetic power to maintain the plasma. The flow of reactive gas is varied and the pressure values in the reactor are measured. The hysteresis curve depends on the target material and the reactive gas selected.

2. - Identification of the flow of critical reactive gas $ c, this being the flow of reactive gas that passes from branch B to branch C of the hysteresis cycle.

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3. - Variation of the reactive gas flow until reaching a value close to but called the critical reactive gas flow value $ c.

4. - Adjusting the angle of incidence of the species through the inclination of the substrate, to obtain the stoichiometry to be achieved,

The proposed way of controlling the stoichiometry of oxides, nitrides or other compounds using reactive magnetron sputtenng by adjusting the angle of incidence of the target species has been successfully tested for a wide variety of metals (Ti, Si, Al, Cr, V, etc.) and mixed targets, two preferred embodiments of the same being presented for Ti and Si, characterized by presenting two different hysteresis cycles.

In the case of the deposition of Ti (Si) and its oxides and sub-oxides, the hysteresis cycle measured as a function of the oxygen flow in the reactor is presented in Figure 3a (3b). These hysteresis curves are similar to the generic curve represented in Figure 1, being possible to perfectly identify the A-F sections defined above. In these hysteresis curves it is also possible to identify the critical reactive gas flow (in this case oxygen) $ c for which the transition from the metallic mode to the reactive mode occurs, the value found in this case being 2.6 sccm for the case of Ti, and 3 sccm for the case of Si.

To obtain TiOx and SiOx, where x can vary between 0 and 2, the steps to be followed in order to adjust the stoichiometry would be the following:

1) Prior characterization of the target or Ti cathode (Si) by obtaining its hysteresis curve in the reactor used, setting a distance from the substrate to the target, electromagnetic power to maintain the plasma, and injecting up to 5 sccm of oxygen. The hysteresis curve is obtained by representing the gas pressure in the reactor as a function of the reactive gas flow.

2) Identification of the critical O2 flow produced by the transit in the hysteresis curve of section B to C, in this example concrete 2.6 sccm for the target Ti and 3 sccm for the Si.

3) Increase in the flow of O2 until reaching 2 sccm in the case of Ti and Si, thus ensuring deposition in the cathode metal mode (Zone B of Figure 1).

4) Modification of the average incidence angle of the pulverized species of the cathode, rotating with respect to the surface of the target an angle between 0 ° and 85 °.

Figure 4a (4b) shows the change in stoichiometry of the coatings by varying the angle in the case of the Ti target (Si). In both cases we can see that

they reach values of x that depend on the angle between white and substrate reaching values close to 2 for high values of the angle between white and substrate (for example x reaches values of 1.5 and 1.63 for Ti and Si at an angle of 70 ° , being x = 2 at 85 ° in both cases) which in conventional mode are only achieved in branches C, D and E of the hysteresis graph.

Figure 5a (5b) shows the growth rates, in atoms per second and square meter, obtained by the backscatter Rutherford Spectroscopy (RBS) of fully stoichiometric samples (TiO2 and SiO2) obtained by working in the reactive mode (E / D branches) and normal geometry and in metallic mode and

10 flush geometry (section B). In both cases, the proposed method improves the growth rate of the conventional technique by a factor greater than 4. The deposition data in these four cases appears in Table I, obtaining stoichiometric layers of both oxides that have a nanocolumnar microstructure such and as shown in Figure 6.

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Table I.- Experimental conditions used to deposit TiO2 and SiO2 by the conventional method and the proposed invention.

 TiO2 Method TiO2 SiO2 Method SiO2

 Conventional Invention Conventional Invention

 Proposal Proposal

 Electromagnetic Power

 300 W (DC) 200 W (pulsed DC, 80 kHz, “off” time 5 ^ s)

 White Distance - Movie

 7 cm

 THE

 0.41 (u = 3) 0.36 (u = 2)

 Composition and

 Ti [circular, diameter: 7.62 cm (3 Si [circular, diameter: 7.62 cm (3

 White Size

 inches)] inches)]

 Partial Pressure Ar

 0.2 Pa

 O2 flow

 2.4 sccm (branch E, fig. 1) 2.4 sccm (branch B, fig. 1) 4 sccm (branch D, fig. 1) 2 sccm (branch B, fig. 1)

 Tilt angle of substrate 1

 0 ° 80 ° 0 ° 85 °

1.The angle of incidence of the target species is 90 ° and 10 ° for substrate inclinations of 0 ° and 80 °, respectively.

Claims (14)

5 10 fifteen twenty 25 30 1. - Procedure for the deposition of thin layers of stoichiometry controlled on substrates by means of sputtering angle reactive sputtering comprising the following steps: - placing the substrate on which the deposition of the thin layer in the reactor that contains a blank that acts as a cathode, which provides material to deposit, will occur. - application of an electromagnetic power that induces an average cathode voltage between 50 V and 10 kV in the presence of a mixture of inert and reactive gases at a total pressure between 10 "2 Pa and 10 Pa where the contribution of the reactive gas It is between 0.1% and 50%. - ignition of a plasma that pulverizes the cathode emitting species that leave it with energies between 10 "2 eV and 100 eV. - deposition of said species, together with others from the reactive gas, as a thin layer on the substrate. - determination of the critical value of reactive gas flow in the reactor from which cathode poisoning occurs resulting in a variation greater than 5% of the total pressure in the reactor and a decrease in deposition rate greater than 50% , characterized in that the flow of the reactive gas in the reactor is selected to be between 0% and 99% of its previously determined critical value and because the substrate is arranged in a geometric configuration with respect to the cathode so that the pulverized species from this they reach the surface of the substrate according to an average flush angle, measured with respect to it, with values between 0 ° and 85 °. 2. - Method of deposition of thin layers of stoichiometry controlled on substrates by means of flush reactive sputtering according to claim 1, characterized in that the electromagnetic power is applied by a source operating in DC, pulsed DC or radiofrequency. 3. - Procedure of deposition of thin layers of stoichiometry controlled on substrates by sputtering reactive sputtering according to claims 1 or 2, characterized in that the materials for the substrate are selected from polymers, glass, quartz, silicon, metals, stainless steel , sapphire or similar. 4. - Procedure of deposition of thin layers of stoichiometry controlled on substrates by sputtering reactive sputtering according to any one of claims 1 to 3, characterized in that the materials to be deposited are selected from compounds of Ti, Si, Al, Cr, V, Zr, other metals or combinations thereof. 5 5. - Method of deposition of thin layers of stoichiometry controlled on substrates by sputtering reactive sputtering according to any one of claims 1 to 4, characterized in that the inert gas is selected from Ar, He, Kr or combinations thereof and The reactive gas is selected from O2, N2, 10 hydrocarbons or combinations thereof. 6. - Procedure of deposition of thin layers of stoichiometry controlled on substrates by means of reactive sputtering sputtering according to any one of claims 1 to 5, characterized in that the average flush angle with which 15 the pulverized species reach the surface of the substrate is between 0.1 ° and 45 °. image 1 Figure 1 image2 Figure 2 image3 Flow O., (sccm) 3.0 02 flow increases • - Flow of 02 decreases 2.8 • or 2.4 X -0.8 I x —0.15 2.2 SW 2.0 Flow O, (sccm) 02 flow increases • - Flow of 02 decreases 3.0 2.8- x = 2 2.6- x = 0.7 2.2- Uncle 2.0- Stoichiometry (O atoms / Si atoms) Stoichiometry (O atoms / Ti atoms) image4 image5 Figure 5 image6