METHOD FOR DEPOSITTING A STACK OF THIN LAYERS USING AN ION BEAM, USE OF AN ION BEAM AND SUBSTRATE OBTAINED

Abstract

The invention relates to a method for depositing a stack of thin films (14) onto a face (11) of a glass substrate (10) by sputtering, said stack of thin films (14) comprising a silver-based metallic functional layer (140, 180) deposited directly onto a zinc oxide-based ground layer (129, 169), said method comprising the use of an ion source, characterized in that said ground layer (129, 169) is bombarded by ions during part or all of its deposition and exhibits biaxial texturing: - out-of-plane texturing with an out-of-plane mosaic pattern of less than 15°; and - in-plane texturing with an in-plane mosaic pattern of less than 50°. Abstract figure: Figure 1

Description

Title of the invention: METHOD FOR DEPOSITTING A STACK OF THIN LAYERS USING FROM AN ION BEAM, USE OF AN ION BEAM AND RESULTING SUBSTRATE

[0001] The invention relates to a method of depositing a stack of thin films on one face of a glass substrate by sputtering, said stack of thin films comprising a silver-based metallic functional layer deposited directly on a zinc oxide-based ground layer, said method comprising the use of an ion source.

[0002] The invention relates to the use of an ionic source for the deposition of this stack of thin films, the use of an ionic source and a glass substrate coated with this stack of thin films.

[0003] In the following description, the term "functional" qualifying "functional stack" or "functional layer" means "able to act on solar radiation and infrared radiation".

[0004] Glazing incorporating such a substrate can be intended for use in both buildings and vehicles, in view of both, with the same glazing: - to reduce the need for air conditioning and / or prevent excessive overheating, by producing a so-called "solar control" effect and - to reduce the amount of energy dissipated to the outside while maximizing the input of solar energy, producing a so-called "low emissivity" effect.

[0005] Known selective glazing comprises transparent substrates coated with a functional stack including one or more metallic functional layer(s), each arranged between two modules of dielectric or "antireflective" layers. Such glazing improves solar protection while maintaining high light transmission. These functional coatings are generally obtained by a series of deposits made by sputtering, possibly assisted by a magnetic field.

[0006] The invention is particularly interested in substrates coated with a functional stack comprising one or more silver-based functional layer(s).

[0007] It is known for example from international patent applications No. WO 2005 / 00758, WO 2005 / 00759 and WO 2007 / 048963 to provide for the deposition of a stack of thin films on a substrate, said deposition process of the layers comprising the use of an ion source.

[0008] The inventors have discovered that it is possible to obtain a reduction in resistance per square of a silver-based functional layer of at least 10% and on the order of 12%, whether or not the stack undergoes heat treatment.

[0009] Indeed, the inventors discovered that a particular configuration of background layer, under a functional layer, made it possible to achieve this.

[0010] One object of the invention is thus to succeed in developing a new type of thin film stacking with one or more improved metallic functional layer(s).

[0011] The invention thus relates, in its broadest sense, to a method of depositing a stack of thin films on one face of a glass substrate by sputtering, said face having a plane and said stack of thin films comprising a silver-based metallic functional layer deposited directly on a zinc oxide-based ground layer, said method comprising the use of an ion source, said method being remarkable in that said ground layer is bombarded by ions during part or all of its deposition, and preferably only it, and exhibits a biaxial texture:

[0012] - an out-of-plane texturing with an out-of-plane mosaic pattern that is less than 15°, and

[0013] - a textured surface with a mosaic pattern in the surface that is less than 50°, preferably below 26°, or even below 25°.

[0014] Mosaicity is the standard deviation of the distribution of grains; it expresses the alignment of the grains with each other.

[0015] Thus, thanks to this particular ground layer configuration, the metallic functional layer is textured in the plane by an epitaxial effect and therefore exhibits an improved crystallographic state. Advantageously, the present invention can lead to grains that are single crystals.

[0016] Said stack comprises one or more metallic functional layers and may comprise, a single metallic functional layer or two metallic functional layers, or three metallic functional layers, or four metallic functional layers; the metallic functional layers referred to here are, preferably, continuous layers.

[0017] A metallic functional layer preferably comprises predominantly, at least 50% by atomic percentage: Ag; one, several, or each, metallic functional layer is preferably made of silver.

[0018] For the purposes of this invention, "metallic layer" means that the layer does not contain oxygen or nitrogen.

[0019] As is customary, the term “dielectric layer” in the context of the present invention means that, from the point of view of its nature, the layer is “non-metallic” ", that is to say, it contains oxygen or nitrogen, or even both. In the context of the invention, this term means that the material of this layer has an n / k ratio over the entire visible wavelength range (from 380 nm to 780 nm) equal to or greater than 5.

[0020] It is recalled that n denotes the real refractive index of the material at a given wavelength and the coefficient k represents the imaginary part of the refractive index at a given wavelength, or absorption coefficient; the ratio n / k being calculated at a given wavelength identical for n and for k.

[0021] By "directly on" is meant in the sense of the invention that no layer is interposed between the two layers considered.

[0022] For the purposes of this invention, "based on" means that, for the composition of this layer, the reactive elements oxygen, or nitrogen, or both if present, are not considered, and the non-reactive element (for example, silicon or zinc) indicated as constituting the base is present at more than 85% atomic percentage of the total non-reactive elements in the layer. This expression thus includes what is commonly referred to in this technique as "doping," whereas the doping element, or each doping element, may be present in quantities of up to 10% atomic percentage, but without the total dopant exceeding 15% atomic percentage of the non-reactive elements.

[0023] By "biaxial texturing" in the sense of the invention, the texturing is observed along two axes: an axis, called "out of plane", which is perpendicular to the plane of the face on which the stack of thin layers is deposited, and an axis which is located in the plane of the face on which the stack of thin layers is deposited.

[0024] In this document, the terminals are included in the indicated ranges.

[0025] In a particular variant, said ion bombardment is a bombardment of argon, xenon, helium, neon or krypton ions, or even dioxygen.

[0026] In a particular embodiment, said background layer is bombarded for 1 / 15th to 3 / 4 of the deposition time of said background layer, in particular for 1 / 10th to 1 / 2 of the deposition time of said background layer.

[0027] This partial-duration bombardment relative to the spraying is preferably carried out at the beginning of the spraying (discontinuous or continuous spraying).

[0028] Said bombardment is carried out, preferably, with an energy between 100 and 2,000 eV.

[0029] Said ion bombardment is carried out, preferably, at an angle of 45° plus or minus 30°, preferably plus or minus 15°, with respect to the plane of said face of the substrate.

[0030] Said ground layer can be deposited by reactive spraying using a zinc metallic target or from a ZnO ceramic target, said target being pure but preferably doped with aluminium and / or tin, said doping by a single element or by all elements preferably being between 0.5 and 15.0 atomic % of the total metallic elements.

[0031] Said base layer preferably has a thickness between 1.0 and 80.0 nm, or even between 2.0 and 50.0 nm.

[0032] Said stack of thin films may comprise several functional metallic silver-based layers each deposited directly on a zinc oxide-based ground layer, and each ground layer is then, preferably, bombarded by ions during part or all of its deposition, and preferably only them, and they each exhibit a biaxial texturing: - an out-of-plane texturing with an out-of-plane mosaicity which is less than 15°; and - an in-plane texturing, with an in-plane mosaicity which is less than 50°, preferably less than 26°, or even less than 25°.

[0033] The present invention also relates to the use of an ionic source for the deposition of a stack of thin films on one face of a glass substrate according to the invention, said base layer being bombarded by ions during part or all of its deposition, and preferably only it, and having a biaxial texture: - an off-plane texture with an off-plane mosaicity that is less than 15°; and - an in-plane texture with an in-plane mosaicity that is less than 50°, preferably less than 26°, or even less than 25°.

[0034] The present invention also relates to a glass substrate, coated on one face with a stack of thin films located on one face of a glass substrate, said face having a plane and said stack of thin films comprising a silver-based metallic functional layer deposited directly on a zinc oxide-based base layer, said stack of thin films being manufactured in particular by the process according to the invention, said base layer having a biaxial texture: - an off-plane texture with an off-plane mosaic that is less than 15°; and - an in-plane texture with an in-plane mosaic that is less than 50°, preferably less than 26°, or even less than 25°.

[0035] Preferably, said base layer is made of zinc oxide doped with aluminum and / or tin, said doping by a single element or by all the elements preferably being between 0.5 and 15.0 atomic % of the total metallic elements.

[0036] The details and advantageous features of the invention will become apparent from the following non-limiting examples, illustrated with the accompanying figures: - [Fig.l] illustrates an example of a functional single-layer stack ending with a terminal protection layer, the functional layer being deposited directly on a background layer and directly under a blocking overlayer; - [Fig.2] illustrates a structure of a functional bilayer stack ending with a terminal protection layer, each functional layer being deposited directly on a base layer and directly under a blocking overlayer; - [Fig.3] shows the difference, from left to right, between an untextured silver functional layer, a silver functional layer textured only out of plane and a silver functional layer textured biaxially, with grains oriented out and in plane; - [Fig. 4] illustrates the in-plane texturing (peak intensity indicated in arbitrary units, as usual), measured by grazing incidence X-ray diffraction (GIXRD), on the left for ZnO along (100) without a beam (center) and with an ion beam (periphery) having an etch / deposition ratio of 20% (400 eV), and on the right, the two resulting values, respectively for silver along (220), without an ion beam (center) and with an ion beam (periphery) with an etch / deposition ratio of 20% (400 eV); and - [Fig.5] illustrates at the top four in-plane textures, measured at grazing incidence (peak intensity shown in arbitrary units), from left to right for silver according to (220), without ion beam, with a 20% (400 eV) ion beam without background layer thickness compensation, with a 20% (400 eV) etch / deposition ratio with background layer thickness compensation to obtain a thickness identical to the first configuration and with a 50% (1000 eV) etch / deposition ratio; and at the bottom four resistance ranges per square without heat treatment, measured for the four top configurations, respectively.

[0037] In [Fig.1] and [Fig.2], the proportions between the thicknesses of the different layers or elements are not strictly respected in order to facilitate their reading.

[0038] Figure 1 illustrates a structure of a single-layer functional stack 14 according to the invention deposited on a face 11 of a transparent glass substrate 10. This diagram illustrates the positions of the different layers relative to each other when these layers are present. The face 11 forms a plane.

[0039] In this structure, the functional layer 140 is silver-based or silver-containing metallic alloy, and is arranged between two antireflective modules: the underlying antireflective module 120 located below the functional layer 140 in the direction of the substrate 10 and the upper antireflective module 160 arranged above the functional layer 140 on the opposite side of the substrate 10

[0040] These anti-reflective modules 120, 160 each comprise at least one dielectric layer 125, 128, 129; 162, 165.

[0041] A terminal protective layer 300, furthest from face 11, can complete the stacking.

[0042] For the illustrated single functional layer stacking structure, the functional layer 140 is located directly on the underlying antireflective module 120 which terminates with a background layer 129 as the layer of the first antireflective module furthest from the face 11 and is located indirectly under the upper antireflective module 160: there is no subblocking layer located between the underlying antireflective module 120 and the functional layer 140 and there is an overblocking layer 150 located between the functional layer 140 and the upper antireflective module 160.

[0043] The single metallic functional layer 140 is designed to reflect infrared radiation and / or a portion of solar radiation. The thickness of the metallic functional layer 140 can typically be between 6 nm and 25 nm, preferably between 10 nm and 20 nm.

[0044] Figure 2 illustrates a multi-layered functional stack 14 structure according to the invention deposited on a face 11 of a transparent glass substrate 10. This diagram illustrates the relative positions of the different layers when these layers are present. The face 11 forms a plane.

[0045] In this structure at least one, and preferably each, functional layer 140, 180, is based on silver or a silver-containing metal alloy, and they are each disposed between two antireflective modules: the underlying antireflective module 120 located below the first functional layer 140 in the direction of the substrate 10 and the intermediate antireflective module 160 disposed above the first functional layer 140 opposite the substrate 10 and below the second functional layer 180. An overlying antireflective module 200 is disposed above the second functional layer 180 opposite the substrate 10.

[0046] These anti-reflective modules 120, 160, 200 each comprise at least one dielectric layer 125, 128, 129; 162, 165, 168, 169, 202, 205.

[0047] A terminal protective layer 300, furthest from face 11, can complete the stacking.

[0048] For the illustrated two-layer functional stacking structure, the first functional layer 140 is located directly on the underlying antireflective module 120, which terminates in a ground layer 129 as the layer of the first antireflective module furthest from face 11, and is located indirectly under the intermediate antireflective module 160: there is no subblocking layer located between the underlying antireflective module 120 and the first functional layer 140, and it there is an overblocking layer 150 located between the first functional layer 140 and the intermediate anti-reflective module 160.

[0049] For the illustrated two-functional-layer stacking structure, the second functional layer 180 is located directly on the underlying intermediate antireflective module 160 which terminates with a background layer 169 as the layer of the intermediate antireflective module 160 furthest from face 11 and is located indirectly under the antireflective module 200: there is no subblocking layer located between the underlying antireflective module 160 and the second functional layer 180 and there is an overblocking layer 190 located between the second functional layer 180 and the last antireflective module 200.

[0050] Each metallic functional layer 140, 180 is designed to reflect infrared radiation and / or a portion of solar radiation. The thickness of each metallic functional layer 140, 180 can typically be between 6 nm and 25 nm, preferably between 10 nm and 20 nm.

[0051] According to preferred embodiments, each metallic functional layer 140, 180, of a multi-layer functional stack is a silver-based layer.

[0052] The anti-reflective modules of stacks with one or more functional layers may comprise one or more layers of oxides and / or nitrides of metallic elements and / or metallic alloys, such as, for example, zinc oxide, mixed zinc and tin oxide, silicon nitride, silicon oxide, zirconium nitride, titanium oxide, tin oxide, and silicon oxynitride.

[0053] The underlying anti-reflective module 120 may include an absorbing layer. The overlying anti-reflective module 200 may include an absorbing layer.

[0054] The substrate 10 also has another face 9, which may have a stack of thin layers or be without a stack of thin layers.

[0055] Thin film deposition processes on substrates, particularly glass substrates, are well known in industry. For example, the deposition of a stack of thin films on a glass substrate is achieved by successively depositing each thin film of said stack by passing the glass substrate through a succession of deposition cells adapted to deposit a given thin film.

[0056] Deposition cells can use deposition methods such as magnetic field-assisted sputtering (also called magnetron sputtering), ion beam-assisted deposition (IBAS), evaporation, chemical vapor deposition (CVD), plasma-assisted chemical vapor deposition (PECVD), low-pressure chemical vapor deposition (LPCVD), etc. These methods can be combined: one part of a stack (a or several layers) can be carried out by one method and one or more other part(s) (one or more layers) can be carried out by one or more other method(s).

[0057] The magnetic field-assisted sputtering deposition process is particularly used. The layer deposition conditions are widely documented in the literature, for example in patent applications WO2012 / 093238 A1 and WO2017 / 00602 A1

[0058] In these stacks with one or more metallic functional layers, a balance must be struck between maximizing reflection in the far-infrared range to minimize heat loss to the outside, maintaining transparency in the visible spectrum for interior comfort, and harnessing solar energy for passive interior heating. Achieving this balance generally involves thin-film stacks with one or more silver-based or silver-containing layers, approximately 10 nm thick (from about 6 to 18 nm), serving as the active element for infrared reflection. According to the Hagens-Rubens relation, the infrared reflectivity of a metal is closely related to its conductivity, making silver an ideal choice due to its low resistivity. Since the nanometric thickness is the result of an infrared / visible trade-off, minimizing the film's resistivity is a key factor in controlling the stack's performance..

[0059] The three parts of [Fig.3] schematically illustrate three different states of a continuous silver metallic layer which is polycrystalline and of which a set of crystal planes is represented by parallel lines at the level of each single crystal (grain), with for each part, at the bottom the visualization of the orientation of the grains in the most favorable XY plane (for example the plane of a main face of a substrate) and at the top, the orientation of the grains outside this plane, along the Z axis.

[0060] The left part illustrates the state of a continuous metallic silver layer deposited on an amorphous (non-crystallised) background layer.

[0061] To improve the crystalline properties of Ag, and thus reduce its resistivity, a polycrystalline zinc oxide ground layer is regularly used beneath the Ag layer. Indeed, it is known that ZnO plays a favorable role in improving the texturing of a silver-based layer deposited on top of it. The central part of [Fig. 3] illustrates this: silver grains are roughly aligned with each other along the Z direction, and some atomic planes (mainly oriented along (111)) are oriented in the same direction, but this texturing of Ag by ZnO only occurs in the out-of-plane orientation. In the plane, all the grains are misoriented, thus creating a polycrystalline structure without a preferred orientation.

[0062] The right-hand part of [Fig.3] illustrates the generation of a biaxial texturing, that is to say both out of plane and in plane, thanks to the invention, thus causing an improvement in the crystallinity of the Ag layers.

[0063] To achieve this, it is proposed to use ion beam assisted sputtering deposition technology or IB AS for "Ion Beam Assisted Sputtering".

[0064] The principle of this technology consists of simultaneously carrying out a reactive deposition by cathodic sputtering of a Zn-based target or a non-reactive target using a ZnO-based target (or a weakly reactive target using a ZnO-based target), and at the same time bombarding the growing ZnO layer with an ion beam.

[0065] For the initial tests, an ion beam gun (Tectra Gen II model) was mounted on a flange in a sputtering coating deposition system, at an angle of 45° to the substrate. The distance between the gun and the sample plane was 217 mm, while the distance between the target and the substrate was 149 mm. The bombardment energy could range from a few eV to 2 keV. The etching rate of the gun was previously calibrated by measurements of ion currents collected by a Ta plate or on Si wafers.

[0066] The ZnO deposition is carried out reactively with a pure Zn metallic target (DC mode, P=50W applied to the target, deposition speed: 0.4 nm / s) with an Ar / O2 gas ratio of 7.5. The base pressure of the chamber is at most 107 mbar, and the working pressure is 3.4.103 mbar.

[0067] The first phase of the study focused on the growth of ZnO films on glass substrates (4 cm x 4 cm) encapsulated by layers of silicon nitride (Si3N4:Al). Different ZnO growth rates (3 minutes deposition time, or approximately 70 nm) were obtained for different gun bombardment energies. The effect of the bombardment can be quantified by taking the ratio between the ablation velocity of the gun and the deposition rate of ZnO. When an energy of IkeV is generated, a ratio of 50% is obtained, corresponding to a thickness half that of the film that was not bombarded by the gun (35 nm instead of 70 nm).

[0068] The two dielectric layers (Si3N4:Al) for the lower and upper layers were deposited in another deposition frame under the following conditions: 2000 W, 2 qbar, Ar flow rate 18 sccm, N2 flow rate: 20 sccm, working pressure of 2.103 mbar, frequency: 50 kHz.

[0069] All these ZnO films were structurally characterized by X-ray diffraction (XRD) measurements, initially focusing on out-of-plane configurations via 0 / 20 measurements. Also, the effect of gun bombardment, simultaneous to growth promotes out-of-plane texturing of ZnO films and an increase in the size of Scherrer crystallites in the growth axis perpendicular to the surface, to a value greater than 3.9 nm (value obtained without IB AS).

[0070] This improvement in the crystalline properties of ZnO films thanks to the invention is also manifested by a decrease in the mosaicity of the out-of-plane films to a value less than 15° (a value greater than 15° is obtained without IB AS). Furthermore, the grain misorientation tends to decrease inversely with the bombardment energy and the ionic flux used, reaching an average misorientation of around 8° for a bombardment energy of IkeV.

[0071] This increase in out-of-plane texturing is also accompanied by in-plane texturing as the bombardment energy increases. On grazing incidence X-ray diffraction (GIXRD) measurements, a 6-symmetry diffraction anisotropy was observed, corresponding to the wurtzite structure of ZnO for films deposited by IB AS. This anisotropy manifests itself as an improvement in the texture coefficient, or Lotgering factor, of the ZnO(lOO) peak, ranging from 16.3% without IB AS to 64.8% for a 1 keV bombardment.

[0072] Table 1 below summarizes the data observed for ZnO.

[0073] [Tables 1] Without IB AS IB AS (10%) IBAS (20%) IBAS (40%) IBAS (50%) Vertical grain size Scherrer (nm) 3.9 4.6 6.0 7.4 7.8 Out-of-plane mosaicity (°) >15 13.5 9.5 9.3 8.1 In-plane mosaicity (°) >100 25.1 25.7 23.0 21.5 Roughness RM S (nm) 0.89 1.55 1.81 - - Texture coefficient for ZnO (100)( %) 16.3 34.2 35.4 58.5 64.8

[0074] However, the atomic force microscopy (AFM) study indicates an increase in the surface roughness of the ZnO films when using the gun at ions, a result contrary to what is observed in the literature where the effect of the IB AS deposition presents the opposite effect of reducing the roughness of the films.

[0075] The second phase of the study focused on stacks with a single 12 nm layer of Ag deposited on textured ZnO, with both layers encapsulated in silicon nitride (Si3N4:Al) films. Ion beam-assisted deposition is performed only on the ZnO film, and the Ag is deposited without the use of an ion-beam gun.

[0076] The diffraction spectra of the ZnO / Ag stacks without and with the use of the ion beam gun were compared: an increase in the combined diffraction peaks of ZnO(002) and Ag(l 11) using ion bombardment is observed, indicating an improved out-of-plane texturing of ZnO and Ag.

[0077] Figure 4 shows that by performing grazing incidence (GIXRD) measurements on these two films targeting the peaks of ZnO(100) and Ag(220), the in-plane texturing generated in the ZnO film using ion bombardment induces in-plane texturing of the Ag deposited on it, with a well-defined anisotropy. This epitaxy occurs in a hexagon / hexagon stacking pattern without rotation in real space (rotation of 60° in reciprocal space) and without lattice shift effects of -11.5%.

[0078] These GIXRD measurements are confirmed by low energy electronic diffraction (LEED) measurements. On a relatively thick Ag film (25 nm) deposited on a textured ZnO film: the diffraction patterns (obtained on the surface of the silver layer with a device present in the deposition frame) confirmed the epitaxy of Ag on the ZnO, and therefore the texturing in the plane of the Ag.

[0079] Next, the evolution of the electrical resistance of biaxially and non-biaxially textured Ag films was studied. Four samples were prepared, for which the Ag layer was 12 nm thick and the ZnO layer was thicker. For the first sample, the ZnO film was not subjected to ion bombardment and was 70 nm thick; for the second, the ZnO grew under an ion bombardment energy of 0.4 keV (20% ratio), leading to a final thickness of 55 nm; the third was identical to the previous one except that the ZnO thickness was compensated to obtain exactly 70 nm; and finally, the last sample used an energy of 1 keV (50% etching / deposition ratio), resulting in a ZnO layer thickness of 35 nm.

[0080] The upper part of [Fig.5] illustrates the in-plane texturing, measured by grazing incidence X-ray diffractions (GIXRD), for the silver layer of the four samples, in this order, from left to right, and the lower part of [Fig.5] illustrates the resistance per square, Rs, of the four samples, in the same order and without any heat treatment.

[0081] Each time, - an improvement in the in-plane texture was observed, it is an increase in the crystalline quality in the plane of a silver layer deposited on a ZnO layer deposited with the IB AS process compared to the same silver layer deposited on the same ZnO layer deposited under standard conditions without simultaneous ion bombardment, (without IB AS); - an improvement in out-of-plane texturing was observed; this is an increase in the out-of-plane crystalline quality of a silver layer deposited on a ZnO layer deposited with the IB AS process compared to the same silver layer deposited on the same ZnO layer deposited under standard conditions without simultaneous ion bombardment (without IB AS); and - a reduction in resistance per square of between 10% and 12% was observed for the three samples treated with IB AS.

[0082] To complete the study, a short anneal at 650°C for 2 min was carried out on each sample and a gain (a decrease in resistance per square) of between 10% and 13% was observed for the three samples treated with IB AS compared to the untreated sample.

[0083] Thinner ZnO thicknesses were also tested: with thicknesses of 5 nm, a gain of 12% is still obtained between the samples treated by IB AS and those not treated, whether before or after annealing at 650°C for 2 min.

[0084] The optical properties of textured films using the Ar ion beam gun were also studied. Table 2 below summarizes the observed data for the resistance per square and the defined energy absorption, measured and calculated in accordance with EN 410.

[0085] [Tables2] Without IBAS With IBAS (20%) (400 eV) ZnO thickness (nm) 570 570 Resistance per square without heat treatment (Q / D) 3.93 3.93 3.43 3.55 Resistance per square after annealing (Q / D) 3.48 3.6 3.02 3.26 Visible absorption without heat treatment (%) 8.9 - 7.9 - Visible absorption after annealing (%) 8.2 - 7.0 -

[0086] It has been observed that the absorption rate in the visible spectrum is reduced by approximately 1% for textured films compared to a film that has not been bombarded by the Ar flux. This 1% absorption gain is also observed when the films are annealed at 650°C for 2 minutes, regardless of the thickness of the ZnO ground layers.

[0087] It has also been observed that these ion beam assisted deposition effects can be optimized by varying the treatment sequence during the deposition of the ground layer. Furthermore, a ZnO deposition in which the ion treatment is stopped after 1 / 9 of the deposition time leads to the observation that the crystallinity of the Ag film improves for the same given thickness (normalized thickness). Indeed, the size of the out-of-plane crystallites ranges from 7.8 nm for simultaneous etching (full IBAS) to 16.2 nm for a deposition where the etching is stopped after 1 / 9 of the deposition time.

[0088] Furthermore, it was tested to perform ion treatment during the deposition of an "AZO" film: the deposition is carried out reactively with a Zn target doped with 2% atomic Al. Two samples were compared, both exhibiting the same structure: a 70 nm thick AZO layer encapsulated by silicon nitride (Si3N4:Al) layers, one of the AZO layers being deposited without the IB AS process and the other with it. By theta / 2theta measurements, an improvement in the size of the out-of-plane crystallites was observed, increasing from 5.9 nm to 6.9 nm with a film deposited by IB AS. Thanks to grazing incidence measurements (GIXRD), a texturing effect in the plane is also observed for the layer deposited by IB AS, with in addition a Lotgering texture coefficient on the ZnO(lOO) increasing from 26% without IB AS to 71% with IB AS.

[0089] In the examples, the functional metallic layers 140, 180 are silver (Ag) layers. The overblocking layers 150, 190 are nickel-chromium alloy (NiCr) metallic layers. The antireflective modules 120, 160, 200 comprise barrier layers, smoothing layers, and backing layers. The barrier layers 125, 165, 205 are silicon nitride-based, such as aluminum-doped silicon nitride (Si3N4:Al) or zirconium-silicon nitride. The smoothing layers 128, 168 are zinc-tin oxide (SnZnOx)-based. The backing layers 129, 169 are zinc oxide (ZnO) or aluminum-doped zinc oxide (AZO).

[0090] [Tables 3] Designation Content Stoichiometry Index (at 550 nm) Si3N4:Al Aluminum-doped silicon nitride m Si3N4:Al 2.05 SiZrN27 Zirconium-silicon nitride SiZrN27 2.40 y / (y + x) = 0.27 ZnO Zinc oxide ZnO 1.90 AZO Aluminum-doped zinc oxide ZnO:Al 1.90 SnZnO Zinc-tin oxide SneZnfO 2.00 NiCr Nickel-chromium alloy NiO,8Cro,2 - Ag Ag -

[0091] The deposition conditions of the layers, which were deposited by sputtering (so-called "magnetron cathode sputtering"), are summarized in Table 4.

[0092] [Tables4] Target Layer Used Deposition Pressure Gas Si3N4 Si:Al at 92:8 wt% 3.2-6.10 3 mbar Ar / (Ar + N2) at 55% SiZrN27 Si:Zr:Al at 68:27:5 wt% 2.103 mbar Ar / (Ar + N2) at 45% ZnO Zn 2.103 mbar Ar / (Ar + O2) at 25% AZO Zn:Al at 98:2 wt% 1.8.103 mbar Ar / (Ar + O2) at 65% SnZnO Zn:Sn at 64:36 wt% 2.103 mbar Ar / (Ar + O2) at 50% NiCr Ni:Cr at 80:20 wt% 2-3.103 mbar Ar at 100% Ag Ag 8.103 mbar Ar at 100%

[0093] at. = atomic

[0094] The present invention is described above by way of example. It is understood that a person skilled in the art is able to carry out different variations of the invention without departing from the scope of the patent as defined by the claims.

Claims

Demands

1. A method for depositing a stack of thin films (14) onto a face (11) of a glass substrate (10) by sputtering, said face (11) having a plane and said stack of thin films (14) comprising a metallic functional layer (140, 180) based on silver deposited directly onto a ground layer (129, 169) based on zinc oxide, said method comprising the use of an ion source, characterized in that said ground layer (129, 169) is bombarded by ions during part or all of its deposition, and preferably only it, and exhibits a biaxial texture: - an out-of-plane texture with an out-of-plane mosaicity that is less than 15°; and - an in-plane texture with an in-plane mosaicity that is less than 50°, preferably less than 26°, or even less than 25°.

2. A method according to claim 1, wherein said ion bombardment is a bombardment of argon, xenon, helium, neon or krypton ions, or even dioxygen.

3. A method according to claim 1 or 2, wherein said ground layer (129, 169) is bombarded for 1 / 15th to 3 / 4 of the deposition time of said ground layer (129, 169).

4. A method according to any one of claims 1 to 3, wherein said bombardment is carried out with an energy between 100 and 2,000 eV.

5. A method according to any one of claims 1 to 4, wherein said base layer (129, 169) is deposited by reactive spraying using a zinc metallic target or a ZnO ceramic target, said target being preferably doped with aluminum and / or tin, said doping with a single element or with all elements being preferably between 0.5 and 15.0 atomic % of the total metallic elements.

6. Method according to any one of claims 1 to 5, wherein said ion bombardment is carried out at an angle of 45° plus or minus 30°, preferably plus or minus 15°, with respect to said face (11) of the substrate (10).

7. A method according to any one of claims 1 to 6, wherein said thin-film stacking (14) comprises several layers metallic functionals (140, 180) based on silver, each deposited directly on a ground layer (129, 169) based on zinc oxide, and wherein each ground layer (129, 169) is bombarded by ions during part or all of its deposition, and preferably only them, and each exhibits a biaxial texturing: - an out-of-plane texturing with an out-of-plane mosaicity that is less than 15°; and - an in-plane texturing with an in-plane mosaicity that is less than 50°, preferably less than 26°, or even less than 25°.

8. Use of an ion source for the deposition of a stack of thin films (14) on a face (11) of a glass substrate (10), according to any one of claims 1 to 7, characterized in that said background layer (129, 169) is bombarded by ions during part or all of its deposition, and preferably only it, and has a biaxial texture: - an out-of-plane texture with an out-of-plane mosaicity which is less than 15°; and - an in-plane texture with an in-plane mosaicity which is less than 50°, preferably less than 26°, or even less than 25°.

9. Glass substrate (10) coated on one face (11) with a stack of thin films (14) located on one face of a glass substrate (10), said face (11) having a plane and said stack of thin films (14) comprising a metallic functional layer (140, 180) based on silver deposited directly on a ground layer (129, 169) based on zinc oxide, said stack of thin films (14) being in particular manufactured by the process according to any one of claims 1 to 7, characterized in that said ground layer (129, 169) has a biaxial texture: - an out-of-plane texture with an out-of-plane mosaic that is less than 15°; and - an in-plane texture with an in-plane mosaic that is less than 50°, preferably less than 26°, or even less than 25°.

10. Substrate (10) according to claim 9, wherein said base layer (129, 169) is made of zinc oxide doped with aluminum and / or tin, said doping with a single element or with all the elements being preferably between 0.5 and 15.0 atomic % of the total metallic elements.

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