WO2023131767A1

WO2023131767A1 - Solar-control and/or low-emissivity glazing

Info

Publication number: WO2023131767A1
Application number: PCT/FR2023/050031
Authority: WO
Inventors: Anne Lelarge; Denis Guimard
Original assignee: Saint-Gobain Glass France
Priority date: 2022-01-10
Filing date: 2023-01-10
Publication date: 2023-07-13
Also published as: FR3131743A1

Abstract

The invention relates to a material comprising a substrate coated with a stack of layers comprising at least one silver-based functional metal layer and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, such that each functional metal layer is arranged between two dielectric coatings, characterised in that the dielectric coating positioned above the functional metal layer comprises: - a zinc-based layer positioned in contact with the functional layer, having a thickness of between 0.3 and 3.0 nm, and - a titanium oxide-based layer positioned above and in contact with the zinc-based layer, having a thickness greater than or equal to 3.0 nm.

Description

Title: Solar control and/or low-emissivity glazing

The invention relates to a material comprising a transparent substrate coated with a functional coating capable of acting on solar radiation and/or infrared radiation. The invention also relates to glazing comprising these materials as well as the use of such materials for manufacturing thermal insulation and/or solar protection glazing. In the remainder of the description, the term “functional” qualifying “functional coating” means “capable of acting on solar radiation and/or infrared radiation”.

These glazings can be intended both to equip buildings and vehicles, in particular with a view to:

- reduce the air conditioning effort and/or prevent excessive overheating, so-called "solar control" glazing and/or

- reduce the amount of energy dissipated to the outside, so-called "low-emission" glazing.

The silver-based functional metal layers (or silver layers) have advantageous properties of electrical conduction and reflection of infrared radiation (IR), hence their use in so-called "solar control" glazing aimed at reducing the amount of incoming solar energy and/or in so-called “low-emission” glazing aimed at reducing the amount of energy dissipated outwards from a building or vehicle.

These silver layers are deposited between coatings based on dielectric materials generally comprising several dielectric layers (hereinafter “dielectric coatings”) making it possible to adjust the optical properties of the stack. These dielectric layers also make it possible to protect the silver layer from chemical or mechanical attack.

When looking to develop solar control glazing, the aim is to reduce the solar factor and increase light transmission and selectivity. When we seek to develop low-emissivity glazing, we seek to reduce emissivity and increase the solar factor. In all cases, the aim is to minimize heat loss.

Emissivity and resistivity (or resistance) per square vary proportionately. Therefore, it is often possible to assess the emissivity of a material by evaluating its resistance per square.

The solar factor of the glazing "FS or g" corresponds to the ratio in % between the total energy entering the room through the glazing and the incident solar energy. The solar factor therefore measures the contribution of glazing to warming the “room”. The lower the solar factor, the lower the solar gain.

The optical and electrical properties such as the emissivity depend directly on the quality of the silver layers such as their crystalline state, their homogeneity as well as their environment. The term "environment" means the nature of the layers close to the silver layer and the surface roughness of the interfaces with these layers. Another way to reduce the emissivity therefore consists in improving the quality of the silver layer by choosing a favorable environment.

To improve the quality of functional metal layers based on silver, it is known to use under the silver layers dielectric coatings comprising dielectric layers with stabilizing function intended to promote wetting and nucleation of the silver layer. . Dielectric layers based on crystallized zinc oxide are notably used for this purpose. Indeed, the zinc oxide deposited by the sputtering process crystallizes without requiring additional heat treatment. The layer based on zinc oxide can therefore serve as an epitaxial growth layer for the silver layer.

Another way to prevent the degradation of the silver layers lies in the choice of the layer located above and in contact with the silver layer. Among the known proposals is the use of so-called blocking layers and/or dielectric layers based on crystallized zinc oxide. The objective is to protect the functional layers from possible degradation during the deposition of the upper dielectric coating and/or during a heat treatment.

The blocking layers are generally based on a metal chosen from nickel, chromium, titanium, niobium, or an alloy of these various metals. The various metals or alloys mentioned can also be partially oxidized, in particular have an oxygen sub-stoichiometry (for example TiOx OR NiCrOx).

These blocking layers are very thin, normally less than 2 nm thick, and are susceptible at these thicknesses to being partially oxidized during heat treatment or during deposition of an overlying layer. In general, these blocking layers are sacrificial layers, capable of capturing oxygen coming from the atmosphere or from the substrate, thus avoiding the oxidation of the silver layer.

Materials comprising above the functional layer(s) based on silver, a sequence of a blocking layer based on an alloy of nickel and chromium and a layer based on zinc oxide are currently used.

However, the use of these thin blocking layers, even associated with stabilizing layers based on zinc oxide, does not make it possible to obtain sufficiently high-performance glazings having in particular a sufficiently low emissivity and good mechanical strength. Indeed, it remains essential according to the invention that the advantageous emissivity properties are obtained without impairing the mechanical strength. Good mechanical resistance translates into good scratch and brush resistance, in particular to the EBT test (“Erichsen brush test”). Good results in terms of resistivity have also been obtained with a material comprising, above the silver-based functional layer(s), a thick layer based on titanium oxide in contact with the silver. This layer is deposited from a sub-stoichiometric ceramic target by controlling the oxygen in the deposition atmosphere. The Ag/TiOx sequence makes it possible to reduce the emissivity. In addition, the presence of this high refractive index layer in contact with the silver contributes:

- to further improve the solar factor in the case where the stack is used as a low-emissivity stack on face 3 in double glazing, or

- to improve discrimination in the case where the stack is used as a solar control stack on face 2 in a double glazing.

However, when using this Ag/TiOx sequence, it is essential to control the oxidation well during the sputtering of the titanium oxide layer. If it is desired to minimize the absorption in the layer based on titanium oxide, a high proportion of oxygen in the deposition atmosphere is required. However, if oxygen is introduced in excess during the sputtering of the first few nanometers of the titanium oxide layer, it causes oxidation of the silver. The resistivity of the silver is then degraded.

Finally, in the absence of oxygen or in the presence of a small quantity of oxygen during the sputtering of the titanium oxide layer, a gain in resistance per square is observed. However, a higher absorption and degraded mechanical properties are also observed. This results in poor EBT test results. The oxygen control used during deposition is a key parameter.

The layer based on titanium oxide is advantageously deposited from a ceramic target, in particular substoichiometric, in a controlled atmosphere comprising oxygen. Preferably, a first thin layer based on titanium oxide is deposited in contact with the silver layer, from a ceramic target, in a non-oxidizing or very weakly oxidizing atmosphere. Then, a thicker thickness of layer based on titanium oxide is deposited from a ceramic target in an oxidizing atmosphere. The layer based on titanium oxide consists of these two parts. During deposition, the part of the titanium oxide-based layer in contact with the functional layer is less oxidized than the part farthest from the functional layer. By doing so, we get:

- low resistance per square thanks to the Ag / TiOx interface deposited without oxygen and

- low absorption thanks to the second part of the titanium oxide layer.

This deposition in several stages makes it possible to obtain mainly in the stack a layer of titanium oxide with a large quantity of oxygen, while protecting the functional layer based on silver from a first layer of titanium oxide. weakly oxidized. The absorption of the stack is then greatly reduced both in the absence of a heat treatment and following a heat treatment.

The Ag/TiOx sequence makes it possible to obtain excellent performance and good durability, provided that the deposition parameters are controlled. However, adjusting these parameters can be quite tricky. It is necessary to determine both the thicknesses and the optimum oxidation conditions for each part of the thick layer of titanium oxide.

There is a need for a solution that can be used industrially with superior performance obtained in a robust and reproducible way, without requiring delicate, long and tedious adjustment time. There is also a need for a solution making it possible to obtain these properties of low emissivity and good mechanical resistance at the same time:

- when the stack or the substrate carrying the stack has not undergone heat treatment at high temperature and

- when the stack or the carrier substrate of the stack undergoes heat treatment at high temperature.

The applicant has surprisingly discovered that the combined use of a zinc-based layer deposited from a metallic zinc cathode associated with a thick titanium oxide-based layer in the dielectric coating located above of the functional layer makes it possible to obtain the advantageous properties without requiring tedious adjustment of the deposition conditions of the layers constituting the stack. Thanks to the presence of the zinc-based layer, the titanium oxide-based layer can be deposited in a single step with high proportions of oxygen while guaranteeing low absorption. Thus, the deposition conditions are simpler and easier to determine industrially than the solution using the Ag/TiOx sequence.

The invention therefore relates to a material comprising a substrate coated with a stack of layers comprising at least one silver-based functional metal layer and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, so that that each functional metallic layer is placed between two dielectric coatings, characterized in that the dielectric coating located above the functional metallic layer comprises:

- a zinc-based layer located in contact with the functional layer having a thickness between 0.3 and 3.0 nm, between 0.3 and 2 nm, between 0.3 and 1 nm or between 0.3 and 0 .8 nm and

- a layer based on titanium oxide located above and in contact with the layer based on zinc having a thickness greater than or equal to 3.0 nm.

The invention resulting from this combination makes it possible to obtain:

- low resistivity values,

- low absorption values, - good mechanical properties of brush resistance without and with heat treatment,

- a simplified deposition process allowing the properties to be obtained in a more robust way.

But above all, the material of the invention has the advantage that these advantageous properties are obtained even when the material coated with the stack or the stack alone has not undergone heat treatment at high temperature. The materials according to the invention can be used interchangeably:

- as deposited, that is to say without having been subjected to any heat treatment at high temperature, in this case neither the substrate coated with the stack, nor the stack alone, has undergone heat treatment at high temperature high,

- treated by laser radiation, in this case, only the stack undergoes heat treatment at high temperature,

- treated by annealing or quenching, in this case the substrate and the stack undergo heat treatment at high temperature.

Obtaining the properties regardless of the presence or not of a heat treatment allows greater flexibility in inventory management. This is of significant economic interest.

The applicant has surprisingly discovered that the combined use of the layer based on zinc, the thick layer based on titanium oxide and a layer based on zinc oxide and particular tin also contributes to obtaining the advantageous properties of the invention. It seems that this layer makes it possible to reduce the residual absorption in the event of incomplete oxidation of the layer based on titanium oxide.

The solution of the invention is particularly suitable in the case of stacks with several functional layers based on silver, in particular stacks with two or three functional layers which are particularly fragile from the point of view of scratches.

The present invention is also particularly suitable in the case of stacks with a single functional layer based on silver intended for applications where, for example, high levels of light transmission are sought.

The material according to the invention may have the following characteristics alone or in combination:

- the zinc-based layer is deposited from a metallic zinc target,

- the layer based on titanium oxide is deposited from a ceramic target, in particular under stoichiometric preferably in an oxidizing atmosphere whose percentage by volume flow rate of oxygen represents between 0 and 20%, preferably 2 to 15 %,

- the layer based on titanium oxide has a thickness of between 5 and 30 nm,

- the layer based on titanium oxide comprises an oxidation gradient, the part of the layer based on titanium oxide in contact with the layer based on zinc is more oxidized than the part the farthest,

- the dielectric coating located above the functional layer comprises a layer based on zinc oxide and tin comprising at least 10% by mass of tin relative to the total mass of zinc and tin, located above and in contact with the layer based on titanium oxide,

- the layer based on zinc oxide and tin has a thickness:

- greater than 5 nm,

- less than 40 nm.

- the dielectric coating located above the functional layer comprises a layer comprising silicon chosen from among the layers of silicon nitride or the layers of silicon nitride and zirconium,

- the dielectric coating located below the functional layer comprises a layer based on zinc oxide located in contact with the functional layer,

- the dielectric coating located below the functional layer comprises a layer comprising silicon chosen from among the layers of silicon nitride or the layers of silicon nitride and zirconium,

- the dielectric coating located below the functional layer comprises a layer with a refractive index greater than 2.20,

- the layer with a refractive index greater than 2.20 is chosen from layers based on titanium oxide and layers based on silicon nitride and zirconium,

- the thickness of all the layers with a refractive index greater than 2.20 in the dielectric coating located below the functional layer is greater than 10 nm, greater than 15 nm, greater than 20 nm,

- the stack comprises a single functional metallic layer based on silver,

- the stack has been subjected to rapid thermal annealing,

- the stack and the substrate have been subjected to a heat treatment at a high temperature above 500°C such as quenching, annealing or bending.

The invention also relates to:

- a glazing comprising a material according to the invention,

- glazing comprising a material according to the invention mounted on a vehicle or on a building, and

- the process for preparing a material or a glazing according to the invention,

- the use of a glazing according to the invention as solar control and/or low-emission glazing for the building or vehicles,

- a building, a vehicle or a device comprising a glazing according to the invention.

The process for preparing a material according to the invention, the material comprising a substrate coated with a stack of layers comprising at least one metallic layer silver-based functional layer and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, so that each functional metal layer is placed between two dielectric coatings, characterized in that the dielectric coating located above above the functional metal layer includes:

- a layer of zinc deposited in metallic form located in contact with the functional layer and

- a titanium oxide-based layer located above and in contact with the metallic zinc layer.

Throughout the description, the substrate according to the invention is considered laid horizontally. The stack of thin layers is deposited above the substrate. The meaning of the expressions “above” and “below” and “lower” and “higher” should be considered in relation to this orientation. In the absence of specific stipulation, the expressions “above” and “below” do not necessarily mean that two layers and/or coatings are arranged in contact with one another. When it is specified that a layer is deposited "in contact" with another layer or a coating, this means that there cannot be one (or more) interposed layer(s) between these two layers (or layer and coating).

All the luminous characteristics described are obtained according to the principles and methods of the European standards EN 410 relating to the determination of the luminous and solar characteristics of the glazing used in glass for construction. Sunlight entering a building is considered to flow from the exterior to the interior.

According to the invention, the luminous characteristics are measured according to the D65 illuminant at 2° perpendicular to the material mounted in a double glazing:

- TL corresponds to the light transmission in the visible in %,

- Rext corresponds to the external light reflection in the visible in %, observer outside space side,

- Rint corresponds to the interior light reflection in the visible in %, observer on the interior space side,

- a*T and b*T correspond to the colors in transmission a* and b* in the L*a*b* system,

- a*Rext and b*Rext correspond to the colors in reflection a* and b* in the L*a*b* system, observer outside space side,

- a*Rint and b*Rint correspond to the colors in reflection a* and b* in the L*a*b* system, observer on the interior space side.

As explained previously, according to the invention the properties must be obtained even when the stack or the substrate carrying the stack has not undergone heat treatment at high temperature. The present invention therefore relates to the non-heat-treated coated substrate. The stack may not have undergone a heat treatment at a temperature above 500°C, preferably 300°C.

The present invention also relates to the heat-treated material. The heat treatments are chosen from:

- annealing, for example rapid annealing,

- quenching and/or bending.

The material, that is to say the transparent substrate coated with the stack, may have undergone a heat treatment at high temperature. The stack and the substrate may have been subjected to a heat treatment at a high temperature such as quenching, annealing or bending.

It is also possible to heat treat only the stack. In this case, the stack only may have undergone heat treatment.

In these two cases, the stack may have undergone a heat treatment at a temperature above 300°C, preferably 500°C. The heat treatment temperature (at the level of the stack) is greater than 300°C, preferably greater than 400°C, and better still greater than 500°C.

According to the invention, it is possible to carry out rapid thermal annealing (“Rapid Thermal Process”) such as laser annealing or flash lamp annealing. Rapid thermal annealing is for example described in applications WO2008/096089 and WO2015/185848. In these cases, only the stack is subjected to heat treatment. During this type of treatment, each point of the stack is brought to a temperature of at least 300° C. while maintaining a temperature less than or equal to 150° C. at any point on the face of the substrate opposite to that on which locate the stack. This process has the advantage of only heating the stack, without significant heating of the entire substrate.

In the case of laser treatment, the coated materials can be treated using a laser line formed from laser sources such as InGaAs diode lasers or Yb:YAG disc lasers. These continuous sources emit at a wavelength between 900 and 1100 nm. The laser line has a length of the order of 3.3 m, equal to the width 1 of the substrate, and an average FWHM half-width between 45 and 100 μm.

The materials are arranged on a roller conveyor so as to scroll along an X direction, parallel to its length. The laser line is fixed and positioned above the coated surface of the substrate with its longitudinal direction Y extending perpendicularly to the running direction X of the substrate, i.e. along the width of the substrate, in extending across that width.

The position of the focal plane of the laser line is adjusted to be within the thickness of the functional coating when the substrate is positioned on the conveyor. The power area of the laser line at the focal plane is less than 100kW/cm2. The substrate was moved under the laser line at a speed of about 8 m/min.

The stack may therefore have been subjected to rapid thermal annealing in which each point of the stack is brought to a temperature of at least 300°C while maintaining a temperature less than or equal to 150°C at any point on the face. of the substrate opposite to that on which the stack is located.

It is also possible to combine heat treatments. For example, it is possible to perform rapid thermal annealing followed by quenching.

The stack and the substrate may have been subjected to a heat treatment at a high temperature above 500°C such as quenching, annealing or bending. The coated substrate of the stack can be bent or tempered glass.

The stack is deposited by cathode sputtering assisted by a magnetic field (magnetron process). According to this advantageous embodiment, all the layers of the stack are deposited by cathode sputtering assisted by a magnetic field.

In the absence of specific stipulation, the expressions “above” and “below” do not necessarily mean that two layers and/or coatings are arranged in contact with one another. When it is specified that a layer is deposited "in contact" with another layer or a coating, this means that there cannot be one (or more) interposed layer(s) between these two layers (or layer and coating).

Unless otherwise stated, the thicknesses referred to in this document are physical thicknesses and the layers are thin layers. By thin layer is meant a layer having a thickness of between 0.1 nm and 100 micrometers.

In the present description, unless otherwise indicated, the expression "based on", used to qualify a material or a layer as to what it or it contains, means that the mass fraction of the constituent which it or it comprises is at least 50%, in particular at least 70%, preferably at least 90%.

The stack of thin layers comprises at least one functional layer and at least two dielectric coatings comprising at least one dielectric layer, so that each functional layer is placed between two dielectric coatings.

The stack of thin layers can comprise at least two metallic functional layers based on silver and at least three dielectric coatings comprising at least one dielectric layer, so that each functional layer is placed between two dielectric coatings.

The stack of thin layers can comprise at least three functional layers and at least four dielectric coatings comprising at least one layer dielectric, so that each functional layer is placed between two dielectric coatings.

The silver-based metallic functional layers comprise at least 95.0%, preferably at least 96.5% and better still at least 98.0% by weight of silver relative to the weight of the functional layer. Preferably, a silver-based functional metallic layer comprises less than 1.0% by mass of metals other than silver relative to the mass of the silver-based functional metallic layer.

The silver-based metallic functional layers have a thickness:

- greater than 5 nm, 6. nm, 7 nm, 8 nm, 9. nm, 10 nm, 11 nm, 12 nm, 13 nm, 14 nm, 15 nm or 16 nm, and/or

- less than 25 nm, 22 nm, 20 nm, 18, nm.

Dielectric coatings include dielectric layers. By "dielectric layer" within the meaning of the present invention, it should be understood that from the point of view of its nature, the material is "non-metallic", that is to say is not a metal. In the context of the invention, this term designates a material having an n/k ratio over the entire visible wavelength range (from 380 nm to 780 nm) equal to or greater than 5. n designates the index of real refraction of the material at a given wavelength and k represents the imaginary part of the refractive index at a given wavelength; the ratio n/k being calculated at a given wavelength identical for n and for k.

The thickness of a dielectric coating corresponds to the sum of the thicknesses of the layers constituting it. Preferably, the dielectric coatings have a thickness greater than 10 nm, greater than 15 nm, between 15 and 200 nm, between 15 and 100 nm or between 15 and 70 nm.

The dielectric layers of the coatings have the following characteristics alone or in combination:

- they are deposited by cathodic sputtering assisted by a magnetic field,

- they have a thickness generally greater than 2 nm, preferably between 4 and 200 nm.

The dielectric layers, in addition to their optical function, can have various other functions. By way of example, mention may be made of stabilizing layers, smoothing layers, and barrier layers.

The dielectric layers are conventionally chosen from layers based on oxide, based on nitride or based on oxynitride. Layers based on oxide of one or more elements essentially comprise oxygen and very little nitrogen. The oxide-based layers include in particular at least 90% in atomic percentage of oxygen with respect to the oxygen and the nitrogen in said layer. The nitride-based layers essentially comprise nitrogen and very little oxygen. Nitride-based layers comprise at least 90 atomic percent nitrogen relative to the oxygen and nitrogen in said layer. Oxynitride layers include a mixture of oxygen and nitrogen. The layers based on silicon oxynitride comprise 10 to 90% (limits excluded) in atomic percentage of nitrogen with respect to the oxygen and the nitrogen in said layer.

The amounts of oxygen and nitrogen in a layer are determined in atomic percentages relative to the total amounts of oxygen and nitrogen in the layer under consideration.

The dielectric layers are conventionally chosen from:

- layers comprising silicon, aluminum and/or zirconium, optionally doped with at least one other element,

- layers based on zinc and tin oxide,

- layers based on titanium oxide,

- layers based on zinc oxide.

According to the invention, a zinc-based layer is located in contact with the functional layer. In the following paragraphs, the zinc-based layers are defined as they are obtained during deposition. Insofar as these layers are thin, it is not possible to determine with certainty, according to the thicknesses deposited, how this zinc-based layer is modified following the deposition of the titanium oxide layer.

The zinc-based layer is deposited by sputtering from a metallic zinc target. The deposition atmosphere is oxygen-free or contains very little oxygen, preferably oxygen-free, i.e. non-oxidizing. This zinc-based layer is partly oxidized to zinc oxide during the deposition of the titanium oxide-based layer. Following the deposition of the titanium oxide layer, there is preferably no absorption due to the non-oxidation of the metallic zinc. However, when the zinc-based layer is deposited in metallic form, the zinc seems to ally or associate with the silver in the form of an AgZn phase. It is possible to carry out analyzes proving the presence of this AgZn phase. When this phase is detected, there is a strong presumption that the zinc in contact with the silver was indeed deposited from a metallic target in the absence of oxygen or under weakly oxidizing conditions.

The thickness of this layer can be as thin as that of a standard blocking layer (<1 nm), as long as the silver-based functional layer is not found to be degraded by the oxygen present during the deposition of the next layer based on titanium oxide, deposited with more oxygen. It has a thickness between 0.3 and 3.0 nm, between 0.3 and 2 nm, between 0.3 and 1 nm or between 0.3 and 0.8 nm.

The zinc-based layers are deposited in metallic form. The zinc-based layers comprise, at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95%, at least 96%, at least 97%, at least 98%, at least 99% or 100% by mass of zinc relative to the total mass of the elements other than oxygen and nitrogen in the zinc-based layer. The zinc-based layers can be chosen from:

- zinc layers,

- doped zinc layers,

- layers based on zinc alloy.

According to the invention, the term “zinc layer” is understood to mean metallic layers of pure zinc which may nevertheless include some impurities. In this case, the total mass of zinc represents at least 99% by mass compared to the total mass of the elements other than oxygen and nitrogen in the zinc-based layer.

According to the invention, the doped zinc layers comprise at least 90.0%, at least 95%, at least 96%, at least 97% or at least 98% by mass of zinc relative to the total mass of the elements other than oxygen and nitrogen in the zinc-based layer.

The doped zinc layers can be chosen from layers based on zinc and at least one element chosen from titanium, nickel, aluminum, tin, niobium, chromium, magnesium, copper, silicon, silver or gold.

According to the invention, the layers based on zinc alloy, comprise at least 20%, at least 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80% or at least 90% by weight zinc based on the total weight of elements other than oxygen and nitrogen in the zinc-based layer.

The layers based on a zinc alloy can be chosen from layers based on zinc and at least one element chosen from titanium, nickel, chromium, tin. By way of example, mention may be made of binary alloys of zinc and titanium such as Zn2II or ternary alloys based on zinc, nickel and chromium such as ZnNiCr.

The thickness of the zinc-based layer can be:

- greater than or equal to 0.3 nm, greater than or equal to 0.5 nm and/or

- less than or equal to 3.0 nm, less than or equal to 2.0 nm, less than or equal to 1.5 nm, less than or equal to 1.0 nm, less than or equal to 0.8 nm.

The stack comprises at least one titanium oxide-based layer located above and in contact with the zinc-based layer having a thickness greater than equal to 3 nm. The layer is a layer based on titanium oxide over this entire thickness. According to the invention, this layer based on titanium oxide is part of a dielectric coating located above the silver layer. This means that when determining the thickness of this dielectric coating, the thickness of this layer is taken into consideration.

This layer based on thick titanium oxide close to the silver contributes to obtaining the advantageous properties of the invention. This oxide layer is not absorbent and this, a fortiori, when it is mainly deposited from a ceramic target in an oxidizing atmosphere.

The layers based on titanium oxide comprise at least 50%, at least 60%, at least 70%, at least 80%, at least 95.0%, at least 96.5% and better still at least 98.0 % by mass of titanium relative to the mass of all the elements constituting the layer based on titanium oxide other than oxygen.

The layers based on titanium oxide can have a thickness:

- greater than or equal to 3 nm, greater than or equal to 4 nm, greater than or equal to 5 nm, and/or

- less than or equal to 30 nm, less than or equal to 25 nm, less than or equal to 20 nm, less than or equal to 15 nm, less than or equal to 10 nm, less than or equal to 8 nm, less than or equal to 6 nm.

The layers based on titanium oxide can have a thickness between 5 and 30 nm.

The layers based on titanium oxide can include or consist of elements other than titanium and oxygen. These elements can be chosen from silicon, chromium and zirconium. Preferably, the elements are chosen from zirconium. Preferably, the layer based on titanium oxide comprises at most 35%, at most 20% or at most 10% by mass of elements other than titanium relative to the mass of all the elements constituting the layer based on titanium oxide other than oxygen.

The layers based on titanium oxide can be obtained:

- by sputtering,

- from a metallic titanium target or a ceramic target based on titanium oxide, preferably sub-stoichiometric.

When the titanium oxide-based layer is obtained from a metal target, the deposition atmosphere includes significant proportions of oxygen.

The layers based on titanium oxide are preferably obtained from a ceramic target of titanium oxide, preferably sub-stoichiometric in oxygen, in an atmosphere comprising oxygen. The quantity of oxygen in the deposition atmosphere can be adapted according to the desired properties.

The layer based on titanium oxide is preferably deposited from a ceramic target, in particular sub-stoichiometric in an oxidizing atmosphere, preferably of which the percentage by volume flow rate of oxygen represents between 0 and 20%, preferably 2 at 15%.

According to the preferred embodiment, a layer based on titanium oxide is deposited from a ceramic target, in particular substoichiometric. The layer based on titanium oxide can be deposited from a ceramic target of TiO _x under stoichiometric, where x is a number different from the stoichiometry of the titanium oxide TiO2, that is to say different of 2 and preferably less than 2, in particular between 0.75 times and 0.99 times the normal stoichiometry of the oxide. TiOx may in particular be such that 1.5<x<1.98 or 1.5<x<1.7, or even 1.7<x<1.95.

According to the invention, depositing is carried out in an atmosphere comprising an optimized quantity of oxygen to obtain the desired properties. The deposition atmosphere comprises a mixture of noble gases (He, Ne, Xe, Ar, Kr) and oxygen. The noble gas is preferably argon. The following parameters are used to define the conditions for sputtering deposition:

- the deposition pressure,

- the composition of the gases in volume flow (unit sccm "standard cubic centimeter per minute"). According to the invention, the following parameters were used:

- the pressure in the deposition chamber is between 1 and 15 pbar, preferably 2 and 10 pbar or 2 and 8 pbar,

- the deposition atmosphere comprises a mixture of argon and oxygen.

The maximum oxygen threshold may vary to some extent depending on, for example:

- the nature of the TiOx target, in particular its oxygen sub-stoichiometry or

- power,

- the configuration of the cathode sputtering deposition chamber (geometry, places of gas inlets, etc.

Indeed, if a low deposition power is used, the volume flow quantities of oxygen that can be used during the deposition will be lower because the TiOx is deposited more slowly and is therefore more likely to oxidize.

A person skilled in the art is able to define a satisfactory controlled atmosphere by varying these parameters to some extent. A person skilled in the art is in particular perfectly able to determine the power to be applied to the target and the volume flow rates of oxygen and noble gases.

According to one embodiment, the layer based on titanium oxide is deposited from a ceramic target, in particular sub-stoichiometric, in an atmosphere comprising oxygen.

According to one embodiment, a first thin thickness of titanium oxide-based layer is deposited in contact with the zinc-based layer, from a ceramic target, in a slightly oxidizing atmosphere. Then, a thicker thickness of layer based on titanium oxide is deposited from a ceramic target in a more oxidizing atmosphere. The thick titanium oxide-based layer according to the invention consists of these two thicknesses. The part of the titanium oxide-based layer in contact with the zinc-based layer is less oxidized than the furthest part. The layer based on oxide of titanium comprises an oxidation gradient, the part of the titanium oxide-based layer in contact with the zinc-based layer is more oxidized than the furthest part.

The layer based on titanium oxide is below and in contact with a dielectric layer. The dielectric layer can be based on oxide, nitride or oxynitride of one or more elements chosen from silicon, zirconium, titanium, aluminium, tin and/or zinc. Preferably, this dielectric layer has a thickness greater than 5 nm, 8 nm, 10 nm or 15 nm.

The stack can comprise at least one layer comprising silicon or aluminum. Preferably, the dielectric coating located above the functional layer may comprise a layer comprising silicon chosen in particular from silicon nitride layers or silicon nitride and zirconium layers. Each dielectric coating may also include at least one layer comprising silicon.

Layers comprising silicon are extremely stable to heat treatments. For example, no migration of the constituent elements is observed. Therefore, these elements are not likely to alter the silver layer. The layers comprising silicon therefore also contribute to the non-alteration of the silver layers and therefore to obtaining a low emissivity after heat treatment.

The layers comprising silicon comprise at least 50% by mass of silicon relative to the mass of all the elements constituting the layer comprising silicon other than nitrogen and oxygen.

The layers comprising silicon can be chosen from layers based on oxide, based on nitride or based on oxynitride such as layers based on silicon oxide, layers based on silicon nitride and layers based on silicon oxynitride.

Silicon oxide based layers include at least 90% atomic percent oxygen relative to the oxygen and nitrogen in the silicon oxide based layer. The silicon nitride based layers include at least 90% atomic percent nitrogen relative to the oxygen and nitrogen in the silicon nitride based layer. The layers based on silicon oxynitride include 10 to 90% (limits excluded) in atomic percentage of nitrogen relative to the oxygen and nitrogen in the layer based on silicon oxide. Preferably, the layers based on silicon oxide are characterized by a refractive index at 550 nm, less than or equal to 1.55. Preferably, the layers based on silicon nitride are characterized by a refractive index at 550 nm, greater than or equal to 1.95.

The layers comprising silicon can comprise or consist of elements other than silicon, oxygen and nitrogen. These elements can be chosen from aluminum, boron, titanium, and zirconium. Layers comprising silicon can comprise at least 2%, at least 5% or at least 8% by mass of aluminum relative to the mass of all the elements constituting the layer comprising silicon other than oxygen and nitrogen.

The layers comprising aluminum can be chosen from layers based on oxide, based on nitride or based on oxynitride such as layers based on aluminum oxide such as Al2O3, layers based on of aluminum nitride such as AIN and layers based on aluminum oxynitride such as AlOxNy.

The layers based on silicon nitride and on zirconium Si _x Zr _y N _z form part of the layers comprising silicon, in particular layers based on silicon nitride. The refractive index of layers based on silicon nitride and zirconium increases with the increase in the proportions of zirconium in said layer.

The layers based on silicon nitride can comprise aluminum and/or zirconium. Such layers may include, in atomic proportion to the atomic proportion of Si, Zr and Al:

- 50 to 98%, 60 to 90%, 60 to 70 atomic % of silicon,

- 0 to 10%, 2 to 10 atomic % aluminum

- 0 to 30%, 10 to 40% or 15 to 30 atomic % of zirconium.

Preferably, the dielectric coating located above the silver layer comprises a layer comprising silicon. These layers comprising silicon have, in increasing order of preference, a thickness:

- less than or equal to 40 nm and/or

- greater than or equal to 5 nm, greater than or equal to 10 nm or greater than or equal to 15 nm.

Preferably, at least one dielectric coating comprises a layer comprising silicon chosen from layers based on silicon nitride. Preferably, the dielectric coating located above the silver-based functional layer comprises a layer comprising silicon chosen from among the layers based on silicon nitride. Each dielectric coating may comprise a layer comprising silicon chosen from layers based on silicon nitride.

Preferably, the sum of the thicknesses of all the layers comprising silicon in the dielectric coating located above the first silver-based functional metal layer can be greater than 35%, greater than 50%, of the total thickness dielectric coating.

Preferably, the sum of the thicknesses of all the layers comprising silicon based on silicon nitride in each dielectric coating located above the first functional metal layer based on silver can be greater than 35%, greater than 50% , the total thickness of the dielectric coating. The dielectric coating located above the functional layer may comprise a layer based on zinc oxide and tin comprising at least 10% by mass of tin relative to the total mass of zinc and tin, located above and in contact with the layer based on titanium oxide.

The layer based on zinc oxide and tin comprises by mass of tin relative to the total mass of zinc and tin:

- at least 10%, at least 15%, at least 20%, at least 30%, at least 40%, at least 45%, at least 50% or at least 55%,

- at most 90%, at most 80%, at most 70%, at most 65% or at most 60% by mass of zinc.

The layer based on zinc oxide and tin located in the dielectric coating above the functional layer based on silver has a thickness:

- greater than 5 nm, greater than 10 nm, greater than 15 nm, greater than 18 nm,

- less than 40 nm, less than 30 nm, less than 25 nm.

The dielectric coating above the silver layer may include:

- a layer based on zinc,

- a layer based on titanium oxide,

- a layer comprising silicon, preferably a layer based on silicon nitride or a layer based on silicon nitride and zirconium or a combination of these two layers.

The dielectric coating above the silver layer may include:

- a layer based on zinc,

- a layer based on titanium oxide,

- a layer based on zinc oxide and tin comprising at least 10% by mass of tin relative to the total mass of zinc and tin, located above and in contact with the layer based on titanium oxide,

- a layer comprising silicon, located above and in contact with the layer based on zinc oxide and tin, preferably a layer based on silicon nitride or a layer based on silicon nitride and zirconium or a combination of these two layers.

The dielectric coating located below the functional layer may comprise a so-called stabilizing layer which reinforces the adhesion of the functional layer to the layers which surround it. The stabilizing layers are preferably layers based on zinc oxide optionally doped, for example, with aluminum. The zinc oxide is crystallized. The zinc oxide-based layer comprises, in increasing order of preference, at least 90.0%, at least 92%, at least 95%, at least 98.0% by weight of zinc relative to the weight of elements other than oxygen in the layer based on zinc oxide.

According to this embodiment, the dielectric coating located below the functional layer may comprise a layer based on zinc oxide located directly at the functional layer contact. Indeed, it is advantageous to have a stabilizing layer, below and in contact with a functional layer, because it facilitates the adhesion and the crystallization of the silver-based functional layer and increases its quality and its stability. . The metallic functional layer is deposited above and in contact with a layer based on zinc oxide. The layer based on zinc oxide can be deposited from a ceramic target, with or without oxygen or from a metal target. The zinc oxide layers have a thickness:

- at least 1.0 nm, at least 2.0 nm, at least 3.0 nm, at least 4.0 nm, at least 5.0 nm, at least 6.0 nm and/or

- not more than 25 nm, not more than 10 nm, not more than 8.0 nm.

The dielectric coating located below the silver layer may also comprise a layer based on zinc oxide and tin comprising at least 10% by mass of tin relative to the total mass of zinc and tin , located below and in contact with the layer based on zinc oxide.

The stack can therefore comprise one or more layers based on zinc oxide and tin comprising at least 10% by mass of tin relative to the total mass of zinc and tin, located above and contact with the layer based on titanium oxide. The layers based on zinc oxide and tin preferably comprise by mass of tin relative to the total mass of zinc and tin:

- at most 90%, at most 80%, at most 70%, at most 65% or at most 60% by mass of zinc. The layers based on zinc and tin oxide have a thickness:

- greater than 5 nm, and/or

- less than 40 nm, less than 30 nm, less than 25 nm.

The dielectric coating located below the functional layer may comprise a layer comprising silicon chosen from among the layers of silicon nitride or the layers of silicon nitride and zirconium.

The dielectric coating located below the functional layer may include a layer with a refractive index greater than 2.20. The presence of high index layers above and below the silver-based functional layer contributes to obtaining high light transmission.

Among the dielectric layers, a distinction is made, according to their refractive index at 550 nm, between the layers with a low refractive index, the layers with an intermediate refractive index and the layers with a high refractive index. The low to low refractive index layers have a refractive index of less than 1.70. Refractive index layers intermediate have a refractive index of between 1.70 and 2.2. High refractive index layers have a refractive index greater than 2.2.

The high refractive index layers can be chosen from:

- layers based on titanium oxide (n550=2.4),

- layers based on mixed titanium oxide and another component chosen from the group consisting of Zn, Zr and Sn,

- layers based on a layer of zirconium nitride (n 550 = 2.55),

- layers based on silicon nitride and zirconium (n550 nm = 2.20 - 2.40),

- layers based on a layer of zirconium oxide,

- layers based on manganese oxide MnO (n550 = 2.16),

- layers based on a layer of tungsten oxide (n550 = 2.15),

- layers based on a layer of niobium oxide (n550 = 2.30),

- layers based on a layer of bismuth oxide (n 550 = 2.60).

Preferably, the layer with a high refractive index is chosen from layers based on titanium oxide and the layer based on silicon nitride and zirconium.

Preferably, the stack does not include a metallic blocking layer or one based on titanium oxide below and in contact with the functional metallic layer based on silver. In this case, the silver-based functional metallic layer is located above and in contact with a dielectric layer of the dielectric coating. Preferably, this dielectric layer is a stabilizing layer.

The dielectric coating located below the functional layer may comprise a sequence of layers, defined starting from the substrate, chosen from:

- layer based on titanium oxide (high index layer) // layer based on zinc oxide,

- layer based on silicon nitride // layer based on zinc oxide,

- layer based on silicon nitride and zirconium (high index layer) // layer based on zinc oxide,

- layer based on silicon nitride // layer based on silicon nitride and zirconium (high index layer) // layer based on zinc oxide,

- layer based on silicon nitride // layer based on titanium oxide (high index layer) // layer based on zinc oxide,

- layer based on silicon nitride and zirconium (high index layer) // layer based on titanium oxide (high index layer) // layer based on zinc oxide,

- layer based on silicon nitride // layer based on silicon nitride and zirconium // layer based on titanium oxide (high index layer) // layer based on zinc oxide,

- layer based on titanium oxide (high index layer) // layer based on zinc and tin oxide // layer based on zinc oxide,

- layer based on silicon nitride // layer based on zinc oxide and tin // layer with zinc oxide base,

- layer based on silicon nitride and zirconium (high index layer) // layer based on zinc oxide and tin // layer based on zinc oxide,

- layer based on silicon nitride // layer based on silicon nitride and zirconium (high index layer) // layer based on zinc and tin oxide // layer based on zinc oxide,

- layer based on silicon nitride // layer based on titanium oxide (high index layer) // layer based on zinc and tin oxide // layer based on zinc oxide?

- layer based on silicon nitride and zirconium // layer based on titanium oxide (high index layer) // layer based on zinc oxide and tin // layer based on zinc oxide ,

- layer based on silicon nitride // layer based on silicon nitride and zirconium // layer based on titanium oxide (high index layer) // layer based on zinc oxide and tin / / layer based on zinc oxide.

When the stack includes a layer of silicon nitride and a layer of silicon nitride and zirconium, these layers are different, i.e. they are not composed of the same elements in the same proportions.

The dielectric coating located above the functional layer may comprise a sequence of layers, defined starting from the substrate, chosen from:

- the zinc-based layer // the titanium oxide-based layer // the silicon nitride-based layer,

- the layer based on zinc // the layer based on titanium oxide // the layer based on silicon nitride and zirconium,

- the layer based on zinc // the layer based on titanium oxide // layer based on silicon nitride and zirconium // layer based on silicon nitride,

- the zinc-based layer // the titanium oxide-based layer // the zinc and tin oxide-based layer // the silicon nitride-based layer,

- the zinc-based layer // the titanium oxide-based layer // the zinc and tin oxide-based layer // the silicon oxide-based layer,

- the layer based on zinc // the layer based on titanium oxide // layer based on zinc oxide and tin // layer based on silicon nitride and zirconium,

- the layer based on zinc // the layer based on titanium oxide // layer based on zinc oxide and tin // layer based on silicon nitride and zirconium // layer based on silicon nitride,

- the layer based on zinc // the layer based on titanium oxide // layer based on zinc oxide and tin // layer based on silicon nitride // layer based on oxide of zinc and tin, - the zinc-based layer // the titanium oxide-based layer // silicon nitride-based layer // silicon oxide-based layer,

- the layer based on zinc // the layer based on titanium oxide // layer based on zinc oxide and tin // layer based on silicon nitride // layer based on oxide of silicon,

- the layer based on zinc // the layer based on titanium oxide // layer based on silicon nitride and zirconium // layer based on silicon nitride // layer based on silicon oxide.

The stack of thin layers can optionally include a protective layer. The protective layer is preferably the last layer of the stack, that is to say the layer farthest from the coated substrate of the stack (before heat treatment). These layers generally have a thickness of between 0.5 and 10 nm, between 1 and 5 nm, between 1 and 3 nm or between 1 and 2.5 nm. This protective layer can be chosen from a layer of titanium, zirconium, hafnium, silicon, zinc and/or tin, this or these metals being in metallic, oxidized or nitrided form.

According to one embodiment, the protective layer is based on zirconium oxide and/or titanium, preferably based on zirconium oxide, titanium oxide or titanium oxide and zirconium. When determining the thickness of a dielectric coating, the thickness of the protective layer is taken into account.

The transparent substrates according to the invention are preferably made of a rigid mineral material, such as glass, or organic based on polymers (or polymer).

The organic transparent substrates according to the invention can also be made of polymer, rigid or flexible. Examples of polymers suitable according to the invention include, in particular:

- polyethylene,

- polyesters such as polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN);

- polyacrylates such as polymethyl methacrylate (PMMA);

- polycarbonates;

- polyurethanes;

- polyamides;

- polyimides;

- fluorinated polymers such as fluoroesters such as ethylene tetrafluoroethylene (ETFE), polyvinylidene fluoride (PVDF), polychlorotrifluorethylene (PCTFE), ethylene chlorotrifluorethylene (ECTFE), fluorinated ethylene-propylene copolymers (FEP);

- photocrosslinkable and/or photopolymerizable resins, such as thiolene, polyurethane, urethane-acrylate, polyester-acrylate and

- polythiourethanes. The substrate is preferably a glass or glass-ceramic sheet. The substrate is preferably transparent, colorless (it is then a clear or extra-clear glass) or colored, for example blue, gray or bronze. The glass is preferably of the silico-sodo-lime type, but it can also be of borosilicate or alumino-borosilicate type glass. According to a preferred embodiment, the substrate is made of glass, in particular silico-sodo-lime or of polymeric organic material.

The substrate advantageously has at least one dimension greater than or equal to 1 m, or even 2 m and even 3 m. The thickness of the substrate generally varies between 0.5 mm and 19 mm, preferably between 0.7 and 9 mm, in particular between 2 and 8 mm, or even between 4 and 6 mm. The substrate can be flat or curved, even flexible.

As explained above, the solution of the invention is suitable:

- for low-emission applications when an increase in light transmission and solar factor is desired and

- for solar control applications when an increase in selectivity is sought.

The invention also relates to a glazing comprising at least one material according to the invention. The invention relates to glazing which may be in the form of monolithic, laminated and/or multiple glazing, in particular double glazing or triple glazing.

Double glazing has 4 faces, face 1 is outside the building and therefore constitutes the outer wall of the glazing, face 4 is inside the building and therefore constitutes the inner wall of the glazing, faces 2 and 3 being inside the double glazing. The stack according to the invention is on face 2 or face 3.

Triple glazing has 6 faces, face 1 is outside the building and therefore constitutes the outer wall of the glazing, face 6 is inside the building and therefore constitutes the inner wall of the glazing, faces 2 and 3 and 4 and 5 being inside the double glazing. The stack according to the invention can be on face 2, face 3 and/or face 5.

A laminated glazing comprises at least one structure of the first substrate/sheet(s)/second substrate type. The polymer sheet may in particular be based on polyvinyl butyral PVB, ethylene vinyl acetate EVA, polyethylene terephthalate PET, polyvinyl chloride PVC. The stack of thin layers is positioned on at least one of the faces of one of the substrates.

The invention therefore relates to:

- multiple glazing of the double glazing type with the stack on face 2,

- multiple glazing of the double glazing type with the stack facing 3,

- multiple glazing of the triple glazing type with the stack on face 2 and face 5,

- laminated glazing with the stack facing 2 or 3.

These glazings can be mounted on a building or a vehicle. The following examples illustrate the invention.

Examples

I. Preparation of substrates: Stacks, deposition conditions

Stacks of thin layers defined below are deposited on clear soda-lime glass substrates with a thickness of 4 mm. In the examples of the invention:

- the functional layers are layers of silver (Ag),

- the dielectric layers are based on silicon nitride doped with aluminum (SisN4: Al), based on silicon nitride and zirconium doped with aluminum (SiZrN: Al), based on zinc oxide and tin (SnZnO), based on zinc oxide doped with aluminum (ZnO: Al).

TiOx titanium oxide layers are deposited from a TiOx ceramic target with or without oxygen in the deposition atmosphere.

The zinc-based layers are deposited from an aluminum-doped zinc metal target.

The deposition conditions of the layers, which were deposited by sputtering (so-called “magnetron cathode” sputtering), are summarized in Table 1.

[Table 1]

%wt: % by weight; at%: atomic.

Different stacks on glass substrate were tested.

The materials according to the invention are intended to be used:

- as deposited, i.e. without having been subjected to any heat treatment at high temperature, hereinafter BT. Neither the substrate coated with the stack, nor the stack alone, has undergone heat treatment at high temperature,

- treated by laser radiation, hereinafter laser, in this case, only the stack undergoes heat treatment at high temperature,

- treated in the Naber® oven at 650°C for 10 min, hereinafter "Naber®",

- treated by quenching, hereinafter “Tempered”. Laser radiation processing involves processing coated substrates with a laser line formed from a disc laser. The following conditions were used:

- disc laser source: Yb:YAG,

- wavelength: 1030nm,

- width: 60pm,

- power density: 70kW/cm ² .

The square resistance Rsq, corresponding to the resistance referred to the surface, is measured by induction with a Nagy SMR-12.

Brush resistance tests were carried out before and after heat treatment (“Erichsen brush test” before EBT heat treatment, after L-EBT laser heat treatment, after TT-EBT quenching type heat treatment). Each sample is observed after 300 cycles. The Ok boxes indicate good resistance to the EBT or L-EBT test after 300 cycles, i.e. the absence of scratches or delamination. The Nok boxes indicate poor resistance to the EBT or L-EBT test after 300 cycles, i.e. the presence of scratches and/or delamination.

II. First series of tests

The table below lists the materials and the physical thicknesses in nanometers (unless otherwise indicated) of each layer or coating which constitutes the stacks according to their positions with respect to the carrier substrate of the stack.

[Table 2]

_the table below shows all the results, Rsq, Abs, and EBT and L-EBT tests.

[Table 3]

1 . Materials as filed

For the material as deposited (BT), the square resistance and the absorption are both degraded in the case of the use of a layer of titanium oxide deposited in an oxidizing atmosphere in contact with silver (comparison Ref.lc and Ref.l a). This is due to the excessive amounts of oxygen during the deposition of the titanium oxide based layer and the consequent degradation of the silver.

The introduction of the metallic zinc layer prevents degradation of the silver layer even at such thin thicknesses (0.5 nm) and leads to the lowest absorption values (7.1% for the example of the invention 1.1 a compared to the references).

But above all, the EBT of the stack according to the invention is satisfactory whereas this is not the case of the references Ref.lb and Ref.ld comprising in contact with the silver a layer of TiOx deposited without oxygen.

2. Laser-processed materials

For stacks treated with laser, a similar trend is observed. The stacking of the invention leads to the lowest absorptions. The resistance per square is satisfactory.

3. Materials treated with Naber®

In the case of stacks treated with Naber®, the stacks of the invention have both low absorption and low resistance per square and satisfactory mechanical properties.

II. Second series of tests

In these examples, the influence of the presence of a layer of zinc and tin oxide in the dielectric coating located above the silver layer is tested.

[Table 4]

Table 5]

1 . Materials as filed

For the material as deposited (BT), the square resistance and the absorption are both degraded in the case of the use of a layer of titanium oxide deposited in an oxidizing atmosphere in contact with silver (comparison Ref.2c and Ref.2a). This is due to the excessive amounts of oxygen during the deposition of the titanium oxide based layer and the consequent degradation of the silver.

The introduction of the metallic zinc layer prevents degradation of the silver layer even at such thin thicknesses (0.5 nm) and leads to the lowest absorption values (6.4% for the example of the L2a invention compared to the references) and the lowest square resistance values (4.3Q/n).

But above all, the EBT of the stack according to the invention is satisfactory whereas this is not the case of the Ref.2b references comprising in contact with the silver a layer of TiOx deposited without oxygen.

2. Laser-processed materials

For stacks treated with laser, a similar trend is observed. The stack of the invention leads to the lowest values of absorption and resistance per square (4.2% and 3.0Q/n). The introduction of the layer of zinc and tin oxide leads to a notable improvement in the resistance per sheet and the absorption (Lia compared to L2a).

The L-EBT test of the stack according to the invention is satisfactory whereas this is not the case references Ref.2b comprising in contact with the silver a layer of TiOx deposited without oxygen.

3. Materials treated with Naber® or quenching

In the case of stacks treated with Naber®, the stack of the invention leads to the lowest absorption and resistance values per square (4.5% and 3.1 Q/n).

For the case of quenched stacks, the presence of the layer based on zinc oxide and tin in contact with the layer of titanium oxide causes an oxidation-reduction reaction between the TiOx and the SnZnO leading to a degradation of square resistance and absorption. All the stacks comprising the TiOx/SnZnO sequence have degraded performance after quenching. However, surprisingly, the stack of the invention has a lower level of degradation.

Claims

1 . Material comprising a substrate coated with a stack of layers comprising at least one silver-based functional metallic layer and at least two dielectric coatings, each dielectric coating comprising at least one dielectric layer, so that each functional metallic layer is disposed between two dielectric coatings, characterized in that the dielectric coating located above the functional metal layer comprises:

- a zinc-based layer located in contact with the functional layer having a thickness between 0.3 and 3.0 nm, and

2. Material according to the preceding claim, characterized in that the zinc-based layer is deposited from a metallic zinc target.

3. Material according to any one of the preceding claims, characterized in that the layer based on titanium oxide is deposited from a ceramic target, in particular sub-stoichiometric.

4. Material according to any one of the preceding claims, characterized in that the layer based on titanium oxide has a thickness of between 5 and 30 nm.

5. Material according to any one of the preceding claims, characterized in that the layer based on titanium oxide comprises an oxidation gradient, the part of the layer based on titanium oxide in contact with the layer based of zinc is more oxidized than the furthest part.

6. Material according to any one of the preceding claims, characterized in that the dielectric coating located above the functional layer comprises a layer based on zinc oxide and tin comprising at least 10% by mass of tin with respect to the total mass of zinc and tin, located above and in contact with the layer based on titanium oxide.

7. Material according to the preceding claim, characterized in that the layer based on zinc oxide and tin has a thickness:

- greater than 5 nm,

- less than 40 nm.

8. Material according to any one of the preceding claims, characterized in that the dielectric coating located above the functional layer comprises a layer comprising silicon chosen from among the layers of silicon nitride or the layers of silicon nitride and zirconium .

9. Material according to any one of the preceding claims, characterized in that the dielectric coating located below the functional layer comprises a layer based on zinc oxide located in contact with the functional layer.

10. Material according to any one of the preceding claims, characterized in that the dielectric coating located below the functional layer comprises a layer comprising silicon chosen from among the layers of silicon nitride or the layers of silicon nitride and zirconium.

11. Material according to any one of the preceding claims, characterized in that the dielectric coating located below the functional layer comprises a layer with a refractive index at 550 nm greater than 2.20.

12. Material according to the preceding claim, characterized in that the layer with a refractive index greater than 2.20 is chosen from layers based on titanium oxide and layers based on silicon nitride and zirconium.

13. Material according to claim 11 or 12, characterized in that the thickness of all the layers with a refractive index greater than 2.20 in the dielectric coating located below the functional layer is greater than 10 nm.

14. Material according to any one of the preceding claims, characterized in that the stack comprises a single functional metal layer based on silver.

15. Material according to any one of the preceding claims, characterized in that the stack has been subjected to rapid thermal annealing.

16. Material according to any one of claims 1 to 14, characterized in that the stack and the substrate have been subjected to a heat treatment at a high temperature above 500° C. such as quenching, annealing or bending.

17. Process for preparing a material according to any one of claims 1 to 16, the material comprising a substrate coated with a stack of layers comprising at least one functional metallic layer based on silver and at least two dielectric coatings , each dielectric coating comprising at least one dielectric layer, so that each functional metal layer is arranged between two dielectric coatings, characterized in that the dielectric coating located above the functional metal layer comprises: