Low-sheet-resistance high-light-transmittance ITO coating film and preparation method thereof

Abstract

The invention relates to the technical field of ITO coating materials, and provides a low-sheet-resistance and high-light-transmittance ITO coating film and a preparation method thereof.The preparation method comprises the steps that S1, an yttrium-doped zirconium oxide substrate is prepared; s2, performing surface activation on the yttrium-doped zirconium oxide substrate; s3, performing magnetron sputtering in a radio frequency magnetron sputtering chamber, and forming a layer of ITO film on the surface of the yttrium-doped zirconia substrate; and S4, annealing treatment and gradient cooling treatment are carried out. The epitaxial growth of the ITO coating film is optimized through the prepared yttrium-doped zirconia substrate, and the magnetron sputtering, annealing and gradient cooling processes are combined, so that the microstructure of the film is optimized, the carrier mobility and the uniformity and stability of the film are improved, the grain boundary defect and carrier scattering loss in the ITO coating film are reduced, and the performance of the film is improved. The low sheet resistance and high light transmittance of the ITO coating film are synergistically improved, and the obtained ITO coating film has important application value in the fields of high-performance optoelectronic devices, transparent conductive films and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of ITO coating materials, and particularly relates to a low sheet resistance and high light transmittance ITO coating and a preparation method thereof. Background Art

[0002] In the development process of modern optoelectronic devices, intelligent displays, and high-efficiency photovoltaic technologies, transparent conductive thin film (TCO) materials play a crucial role. ITO (indium tin oxide) is widely used in touch panels, OLED displays, solar cells, intelligent windows, and other fields due to its excellent electrical conductivity and high light transmittance. In these applications, the transparent conductive film not only needs to have a low resistivity to ensure efficient electron transport but also needs to have a high light transmittance to maintain high-quality optical performance, reduce light loss, and improve display brightness or photovoltaic conversion efficiency. In addition, with the rapid development of high-resolution display technologies, new flexible electronic devices, and high-efficiency solar cells, higher requirements are put forward for the performance of ITO thin films, such as lower sheet resistance to reduce energy consumption and improve response speed, and higher light transmittance to optimize optical performance, especially to maintain good transparency in the near-ultraviolet and infrared bands. Therefore, in the field of transparent conductive thin films, how to further reduce the sheet resistance of ITO while maintaining or even improving the optical transmittance has become the key to promoting the development of this technology and an important technological breakthrough point for improving the performance and application scope of a new generation of optoelectronic devices.

[0003] Although ITO has been widely used as the preferred material for transparent conductive thin films, the existing ITO thin films still face the challenge of being difficult to balance low sheet resistance and high light transmittance. For example, Chinese Patent No. CN108109722A discloses a method for preparing an ITO thin film, which uses a liquid-phase indium tin oxide precursor combined with annealing to obtain the ITO thin film. However, the film usually has poor crystallinity or crystal form control, so there are certain deficiencies in the electrical conductivity and light transmittance of the film. In addition, the grain orientation and crystallization quality of the existing ITO thin films have an important impact on the conductivity and optical properties, but the existing processes are difficult to precisely control the texture growth of ITO, resulting in enhanced carrier scattering inside the film, thereby increasing the resistance and reducing the light transmittance. At the same time, some studies have tried to improve the conductivity and transparency of ITO by optimizing the doping concentration or changing the deposition atmosphere, but these methods often lead to a decrease in the film stability or cause the complication and cost increase of the preparation process. Therefore, a technical solution that can optimize the ITO crystal structure while taking into account low sheet resistance and high light transmittance is needed to achieve the wider application of transparent conductive thin films in the fields of optoelectronics and display technologies. Summary of the Invention

[0004] (1) Technical Problems to be Solved

[0005] The object of the present invention is to provide a low sheet resistance and high light transmittance ITO coating and a preparation method thereof, so as to solve the problem of insufficient performance of the current ITO coating in terms of sheet resistance and light transmittance.

[0006] (2) Technical solution

[0007] In order to achieve the above object, the present invention provides the following technical solution:

[0008] A preparation method of a low sheet resistance and high light transmittance ITO coating includes the following steps:

[0009] S1. Prepare a yttrium-doped zirconia substrate with a root mean square (RMS) roughness of 0.2 - 0.5 nm;

[0010] S2. Activate the surface of the yttrium-doped zirconia substrate;

[0011] S3. Place the surface-activated yttrium-doped zirconia substrate into a radio frequency magnetron sputtering chamber for magnetron sputtering to form an ITO thin film on the surface of the yttrium-doped zirconia substrate;

[0012] S4. Then perform annealing treatment and gradient cooling treatment to obtain the low sheet resistance and high light transmittance ITO coating.

[0013] The yttrium-doped zirconia substrate prepared by the present invention has high orientation and low defect density, provides a stable lattice matching environment for the epitaxial growth of the ITO thin film, enhances the crystallization quality and interface matching of the ITO thin film, and effectively reduces the accumulation of internal stress in the ITO thin film, thereby improving its structural stability and long-term use reliability, and optimizing its conductivity and light transmittance performance.

[0014] By selecting the yttrium-doped zirconia substrate of the present invention and combining with the optimized steps of magnetron sputtering, annealing treatment and gradient cooling treatment, it is ensured that the obtained ITO coating further optimizes the optical transmission characteristics while maintaining a low sheet resistance, making it have more excellent performance in applications such as optoelectronic devices, transparent electrodes and high-performance display panels.

[0015] Preferably, in the yttrium-doped zirconia substrate, the (200) crystal orientation of the yttrium-doped zirconia is perpendicular to the surface of the yttrium-doped zirconia substrate; the doping amount of yttrium oxide in the yttrium-doped zirconia substrate is 4 - 8 at.%.

[0016] Preferably, the preparation method of the yttrium-doped zirconia substrate includes the following steps:

[0017] Place a clean Si(100) substrate with a surface roughness Ra ≤ 0.2 nm in a multi-cathode sputtering deposition system. The multi-cathode sputtering deposition system includes two DC sputtering sources and one RF sputtering source. The two DC sputtering sources and one RF sputtering source are arranged in a confocal manner and form an angle of 55 - 65 degrees with the substrate normal. Among them, the two DC sputtering sources are used for reactive sputtering of zirconium targets, and the RF sputtering source is used for reactive sputtering of yttrium targets. By reactive co-sputtering two zirconium targets and one yttrium target, deposit a yttrium-doped zirconia substrate in an argon-oxygen mixed plasma, where the volume flow ratio of argon to oxygen is 1.5 - 2.0:1, the total working pressure is 8 - 12 mTorr, and the power density of the zirconium target is 12 - 15 W / cm 2 , and the power density of the yttrium target is 2.0 - 2.5 W / cm 2 . The substrate bias voltage is -300 - -500 V, and the substrate temperature is 70 - 80 °C.

[0018] In the present invention, by depositing a yttrium-doped zirconia thin film on a clean Si(100) substrate, the surface roughness of the substrate is effectively reduced to achieve nanoscale flatness. This optimized substrate surface can significantly improve the epitaxial growth conditions of the ITO coating, reduce the adverse effects of grain boundary scattering on conductivity, and simultaneously improve the optical uniformity of the thin film.

[0019] In the deposition process of the yttrium-doped zirconia thin film, a multi-cathode sputtering system is adopted. Among them, two DC sputtering sources are used for reactive sputtering of zirconium targets, and one RF sputtering source is used for co-deposition of yttrium targets. Each sputtering source is arranged in a confocal manner and forms a specific angle with the substrate normal to precisely control the deposition uniformity and composition distribution of the thin film. By optimizing the volume flow ratio of argon to oxygen, and controlling the sputtering power density, substrate bias voltage, and substrate temperature, ensure the stoichiometry and crystal phase stability of the thin film during the deposition process, thereby obtaining a high-quality yttrium-doped zirconia substrate. This substrate not only provides an excellent lattice matching environment to promote the (400) preferred orientation growth of the ITO thin film, but also can effectively reduce the stress accumulation in the thin film, improving its mechanical stability and long-term reliability. In addition, the optimized deposition environment and parameter regulation can ensure the densification and uniformity of the yttrium-doped zirconia thin film, further reducing the grain boundary defects and carrier scattering losses in the ITO coating, and thus enhancing the electrical and optical properties of the entire transparent conductive film.

[0020] Preferably, the method for preparing the clean Si(100) substrate includes the following steps: Immerse the Si(100) substrate in a hydrofluoric acid solution with a mass fraction of 3.0 - 5.0% to remove the surface oxide layer, then transfer it to a mixed cleaning solution composed of deionized water, hydrogen peroxide with a mass fraction of 25 - 30%, and ammonia water with a mass fraction of 25 - 30% in a volume ratio of 5:1:1, perform ultrasonic treatment at 75 - 85°C for 10 - 20 min, with an ultrasonic frequency of 40 - 60 kHz. The substrate is then rinsed with ultrapure water, the residual liquid on the surface is blown off in a nitrogen atmosphere, and finally placed in a vacuum oven for drying to obtain the product.

[0021] During the preparation of a clean substrate with a surface roughness Ra ≤ 0.2 nm, a hydrofluoric acid solution is used to remove the surface oxide layer to ensure that the Si(100) surface is pure and pollution-free. Subsequently, a mixed cleaning solution containing hydrogen peroxide and ammonia water is used for ultrasonic treatment to further remove organic pollutants and particulate impurities. Thereafter, through the steps of rinsing with ultrapure water, nitrogen blowing, and vacuum drying, the substrate surface reaches an ultra-low roughness, providing ideal conditions for the deposition of the yttrium-doped zirconia thin film.

[0022] Preferably, the surface activation of the yttrium-doped zirconia substrate includes the following steps: Place the yttrium-doped zirconia substrate in a plasma cleaning chamber, introduce a mixed gas of argon and oxygen with a volume flow ratio of 1:1, and perform radio frequency plasma treatment for 10 - 15 min under the conditions of a power density of 0.5 - 1.0 W / cm 2 and a pressure of 5 - 10 mTorr.

[0023] By performing surface activation treatment on the yttrium-doped zirconia substrate, adsorbed impurities are effectively removed and the surface energy state is optimized, enabling it to have better interfacial bonding ability, thereby providing a stable substrate environment for the epitaxial growth of the subsequent ITO film layer.

[0024] Preferably, the process parameters of the magnetron sputtering include: Using a mixed gas of argon and oxygen as the working gas, where the volume flow ratio of oxygen to argon is 20 - 40:40 - 60, the total working pressure is 3.0 - 5.0 mTorr, using an ITO target, the content of SnO2 in the ITO target is 8.5 - 9.5 wt%, the power density of the target is 8.5 - 11.5 W / cm 2 , the substrate bias voltage is -100 - -150 V, the substrate temperature is 255 - 295°C, the substrate rotation rate is 5 - 10 rpm, the deposition rate is 3.0 - 5.0 nm / min, the deposition time is 35 - 55 min, the plasma density is 1×10 10 - 5×10 10 cm -3 , and the film thickness uniformity deviation ≤ ±3%.

[0025] During the radio frequency magnetron sputtering process, by precisely controlling the volume flow ratio of argon to oxygen, the total working pressure, and the substrate temperature, the microstructure of the ITO thin film is regulated, while promoting the densification of the ITO thin film to reduce carrier scattering and improve the conductivity. In addition, the adjustment of the substrate bias voltage helps to enhance the adhesion of the ITO thin film and optimize the nucleation process, enabling the ITO film layer to maintain a high-quality crystal orientation.

[0026] Preferably, the process parameters of the annealing treatment include: continuously introducing a mixed gas of hydrogen and nitrogen, the volume flow rate of hydrogen accounting for 3.5 - 4.5% of the volume flow rate of the mixed gas, the pressure in the annealing furnace being 1 - 5 Torr, the heating rate being 6 - 9 °C / min, the constant temperature being 420 - 540 °C, the constant temperature time being 40 - 50 min, and the temperature fluctuation during the constant temperature period being ≤ ±2 °C.

[0027] The present invention adopts an annealing treatment in a hydrogen-nitrogen mixed atmosphere. Through appropriate gas composition ratio and temperature control, the crystallinity of the ITO thin film is further optimized, crystal boundary defects are reduced, the electron mobility is improved, and at the same time, the optical properties of the thin film are improved, and the free carrier absorption effect is reduced.

[0028] Preferably, the process parameters of the gradient cooling treatment include: in the first stage, cooling from the annealing temperature to 200 - 230 °C at a rate of 3 - 4 °C / min, and in the second stage, cooling to room temperature at a rate of 1 - 2 °C / min. The whole process maintains a nitrogen protection atmosphere with an oxygen content ≤ 1 ppm, and finally a low sheet resistance and high transmittance ITO coating is obtained.

[0029] The present invention adopts a gradient cooling process to reduce the accumulation of thermal stress in a staged cooling manner, and suppresses the oxidation and phase transformation of the thin film under a nitrogen protection environment, ensuring that the final ITO coating simultaneously has excellent conductivity and high transmittance. The optimization of the process parameters in each link acts synergistically, enabling the ITO coating to further improve the optical uniformity and long-term environmental stability while maintaining a low sheet resistance, thereby meeting the requirements of high-performance optoelectronic devices for high-quality transparent conductive thin films.

[0030] As a general inventive concept, the present invention provides a low sheet resistance and high transmittance ITO coating prepared by a method for preparing a low sheet resistance and high transmittance ITO coating. The low sheet resistance and high transmittance ITO coating is located on a yttrium-doped zirconia substrate; the low sheet resistance and high transmittance ITO coating is an ITO(400) strong texture; the (400) crystal orientation of the ITO(400) strong texture is perpendicular to the surface of the yttrium-doped zirconia substrate; and the ITO(400) strong texture has a columnar crystal morphology, and the average lateral size of the columnar crystal grains is 100 - 150 nm.

[0031] By growing an ITO coating on the yttrium-doped zirconia substrate of the present invention, high-quality epitaxial growth is achieved. The formation of strong texture of ITO(400) in the ITO coating makes the grain orientation inside the film more uniform, optimizes the microstructure of the film, improves the carrier mobility, reduces the scattering loss of carriers at grain boundaries, and the introduction of columnar crystal morphology also helps to reduce the lateral carrier scattering. Therefore, the yttrium-doped zirconia substrate is used in the present invention to cooperate with the strong texture epitaxial growth of ITO(400), effectively enhancing the electrical conductivity and light transmittance of the ITO coating.

[0032] Preferably, a coherent interface is formed between the yttrium-doped zirconia substrate and the low sheet resistance and high light transmittance ITO coating;

[0033] The proportion of small-angle grain boundaries of 2-5° in the low sheet resistance and high light transmittance ITO coating is 72.0-85.0%, and the twin density is 10 5 ~4.5×10 6 cm-2.

[0034] By optimizing the grain boundary structure in the present invention, the proportion of small-angle grain boundaries of 2-5° in the ITO coating reaches a relatively high level, and at the same time, the twin density is controlled within a specific range to suppress the adverse effects of grain boundary states on electron transport.

[0035] (3) Beneficial technical effects

[0036] By optimizing the epitaxial growth of the ITO coating with the yttrium-doped zirconia substrate and combining precisely controlled magnetron sputtering, annealing, and gradient cooling processes in the present invention, the microstructure of the film is optimized, the carrier mobility, film uniformity, and stability are improved, the grain boundary defects and carrier scattering losses in the ITO coating are reduced, the simultaneous improvement of low sheet resistance and high light transmittance of the ITO coating is achieved, and the obtained ITO coating has important application value in the fields of high-performance optoelectronic devices and transparent conductive films, thus promoting the technological upgrading of the industry. Description of the drawings

[0037] Figure 1 It is the XRD phase analysis diagram of the low sheet resistance and high light transmittance ITO coating prepared in Example 1 of the present invention.

[0038] Figure 2 It is the cross-sectional microstructure morphology diagram of the low sheet resistance and high light transmittance ITO coating prepared in Example 1 of the present invention.

[0039] Figure 3 It is the interface diagram between ITO(400) and the yttrium-doped zirconia substrate in the low sheet resistance and high light transmittance ITO coating prepared in Example 1 of the present invention.

[0040] Figure 4 It is the surface roughness diagram of the yttrium-doped zirconia substrate prepared in Example 1 of the present invention.

[0041] Figure 5 XRD phase analysis diagram of the ITO coating prepared in Comparative Example 1 of the present invention.

[0042] Figure 6 Surface roughness map of the yttrium-doped zirconia substrate prepared in Comparative Example 3 of the present invention. Detailed implementation manners

[0043] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0044] Example 1:

[0045] A preparation method of a low sheet resistance and high light transmittance ITO coating, comprising the following steps:

[0046] S1. Prepare a yttrium-doped zirconia substrate:

[0047] Place a clean Si(100) substrate with a surface roughness Ra≤0.2nm in a multi-cathode sputtering deposition system, which includes two DC sputtering sources and one RF sputtering source. The two DC sputtering sources and one RF sputtering source are arranged in a confocal manner and form an angle of 55 degrees with the substrate normal. Among them, the two DC sputtering sources are used for reactive sputtering of zirconium targets, and the RF sputtering source is used for reactive sputtering of yttrium targets. Deposit the yttrium-doped zirconia substrate in an argon and oxygen mixed plasma by reactive co-sputtering two zirconium targets and one yttrium target, where the volume flow ratio of argon to oxygen is 1.5:1, the total working pressure is 8 mTorr, the power density of the zirconium target is 12 W / cm 2 , and the power density of the yttrium target is 2.0 W / cm 2 , the substrate bias voltage is -300V, and the substrate temperature is 70°C.

[0048] In the above yttrium-doped zirconia substrate, the (200) crystal orientation of the yttrium-doped zirconia is perpendicular to the surface of the yttrium-doped zirconia substrate; the root mean square roughness of the yttrium-doped zirconia substrate is 0.2nm; the doping amount of yttrium oxide in the yttrium-doped zirconia substrate is 4 at.%.

[0049] The preparation method of the clean Si(100) substrate is as follows: Place the commercial Si(100) substrate in a hydrofluoric acid solution with a mass fraction of 3.0% and soak it for 5 min to remove the surface oxide layer. Subsequently, transfer it to a mixed cleaning solution composed of deionized water, hydrogen peroxide with a mass fraction of 25%, and ammonia water with a mass fraction of 25% in a volume ratio of 5:1:1, and perform ultrasonic treatment at 75 °C for 10 min with an ultrasonic frequency of 40 kHz. After the substrate is rinsed 3 times with ultrapure water, blow the residual liquid on the surface at a flow rate of 10 L / min in a nitrogen atmosphere. Finally, place it in a vacuum oven and dry it at 120 °C and -0.08 MPa for 30 min to obtain a clean Si(100) substrate with a surface roughness Ra ≤ 0.2 nm.

[0050] S2. Surface activation of the yttrium-doped zirconia substrate:

[0051] Place the yttrium-doped zirconia substrate in a plasma cleaning chamber, introduce a mixed gas of argon and oxygen with a volume flow ratio of 1:1, and perform 10 min of radio frequency plasma treatment under the conditions of a power density of 0.5 W / cm 2 and a pressure of 5 mTorr.

[0052] S3. Put the surface-activated yttrium-doped zirconia substrate into a radio frequency magnetron sputtering chamber for magnetron sputtering to form an ITO thin film on the surface of the yttrium-doped zirconia substrate;

[0053] The process parameters of magnetron sputtering include: using a mixed gas of argon and oxygen as the working gas, where the volume flow ratio of oxygen to argon is 20:40, the total working pressure is 3.0 mTorr, using an ITO target, the content of SnO2 in the ITO target is 8.5 wt%, the target power density is 8.5 W / cm 2 , the substrate bias voltage is -100 V, the substrate temperature is 255 °C, the substrate rotation rate is 5 rpm, the deposition rate is 3.0 nm / min, the deposition time is 35 min, and the plasma density is 1×10 10 cm -3 , and the film thickness uniformity deviation ≤ ±3%.

[0054] S4. Then perform annealing treatment and gradient cooling treatment to obtain the low sheet resistance and high light transmittance ITO coating.

[0055] The process parameters of the annealing treatment include: continuously introducing a mixed gas of hydrogen and nitrogen, the volume flow of hydrogen accounts for 3.5% of the volume flow of the mixed gas, the total flow of the mixed gas is 500 sccm, the pressure in the furnace is 1 Torr, the heating rate is 6 °C / min, the constant temperature is 420 °C, the constant temperature time is 40 min, and the temperature fluctuation during the constant temperature period ≤ ±2 °C.

[0056] The process parameters of the gradient cooling treatment include: cooling from the annealing temperature to 200 °C at a rate of 3 °C / min in the first stage, and then cooling to room temperature at a rate of 1 °C / min in the second stage. The nitrogen protection atmosphere is maintained throughout the process with an oxygen content ≤ 1 ppm, and finally a low sheet resistance and high light transmittance ITO coating is obtained.

[0057] The low sheet resistance and high light transmittance ITO coating of this embodiment is located on a yttria-stabilized zirconia substrate; the ITO coating is a strongly textured ITO(400); the (400) crystal orientation of the strongly textured ITO(400) is perpendicular to the surface of the yttria-stabilized zirconia substrate; the strongly textured ITO(400) has a columnar crystal morphology, and the average lateral size of the columnar crystal grains is 100 nm. A coherent interface is formed between the yttria-stabilized zirconia substrate and the low sheet resistance and high light transmittance ITO coating; the proportion of 2° small angle grain boundaries in the ITO coating is 72.0%, and the twin density is 4.5×10 5 cm-2.

[0058] Figure 1 The XRD phase analysis results of the low sheet resistance and high light transmittance ITO coating prepared in Example 1 of the present invention are shown. The presence of the diffraction peaks of Si(100), ITO(400) and YSZ(200) proves that the crystallization quality of the ITO thin film is good, and it has been successfully grown on the preferentially oriented YSZ substrate. Figure 2 The cross-sectional microstructure morphology diagram further proves that the ITO thin film exhibits an obvious columnar crystal structure, which helps to improve its electrical and optical properties. At the same time, Figure 3 it can be seen that a good coherent interface is formed between ITO(400) and the yttria-stabilized zirconia substrate, indicating that the ITO thin film and the YSZ substrate have good lattice matching and epitaxial relationship. Figure 4 The surface roughness measurement results of the yttria-stabilized zirconia substrate prepared in Example 1 are shown. The root mean square surface roughness (RMS) is only 0.2 nm, indicating that the substrate surface is relatively flat, which helps the uniform growth of the ITO thin film.

[0059] Example 2:

[0060] A method for preparing a low sheet resistance and high light transmittance ITO coating, comprising the following steps:

[0061] S1. Prepare a yttria-stabilized zirconia substrate:

[0062] A clean Si(100) substrate with a surface roughness Ra ≤ 0.2 nm is placed in a multi-cathode sputtering deposition system, which includes two DC sputtering sources and one RF sputtering source. The two DC sputtering sources and one RF sputtering source are arranged in a confocal manner and are at an angle of 58 degrees with the substrate normal. Among them, the two DC sputtering sources are used for reactive sputtering of zirconium targets, and the RF sputtering source is used for reactive sputtering of yttrium targets. By reactive co-sputtering two zirconium targets and one yttrium target, a yttrium-doped zirconia substrate is deposited in a mixed plasma of argon and oxygen, where the volume flow ratio of argon to oxygen is 1.7:1, the total working pressure is 9 mTorr, the power density of the zirconium target is 13 W / cm 2 , and the power density of the yttrium target is 2.2 W / cm 2 , the substrate bias voltage is -360 V, and the substrate temperature is 73 °C.

[0063] In the above yttrium-doped zirconia substrate, the (200) crystal orientation of the yttrium-doped zirconia is perpendicular to the surface of the yttrium-doped zirconia substrate; the root mean square roughness of the yttrium-doped zirconia substrate is 0.3 nm; the doping amount of yttrium oxide in the yttrium-doped zirconia substrate is 5 at.%.

[0064] The preparation method of the clean Si(100) substrate is as follows: The commercial Si(100) substrate is immersed in a hydrofluoric acid solution with a mass fraction of 3.6% for 7 min to remove the surface oxide layer, and then transferred to a mixed cleaning solution composed of deionized water, hydrogen peroxide with a mass fraction of 26%, and ammonia water with a mass fraction of 26% in a volume ratio of 5:1:1, and ultrasonically treated at 78 °C for 13 min, the ultrasonic frequency is 46 kHz. After the substrate is rinsed 4 times with ultrapure water, the surface residual liquid is blown off at a flow rate of 12 L / min in a nitrogen atmosphere, and finally placed in a vacuum oven and dried at 129 °C and -0.09 MPa for 39 min to obtain a clean Si(100) substrate with a surface roughness Ra ≤ 0.2 nm.

[0065] S2. Surface activation of the yttrium-doped zirconia substrate:

[0066] The yttrium-doped zirconia substrate is placed in a plasma cleaning chamber, and a mixed gas of argon and oxygen with a volume flow ratio of 1:1 is introduced, and radio frequency plasma treatment is carried out at a power density of 0.7 W / cm 2 and a pressure of 7 mTorr for 12 min.

[0067] S3. The surface-activated yttrium-doped zirconia substrate is placed in a radio frequency magnetron sputtering chamber for magnetron sputtering to form an ITO thin film on the surface of the yttrium-doped zirconia substrate;

[0068] The process parameters of magnetron sputtering include: using a mixed gas of argon and oxygen as the working gas, where the volume flow ratio of oxygen to argon is 26:46, the total working pressure is 3.6 mTorr, using an ITO target, the SnO2 doping amount of the ITO target is 8.8 wt%, and the target power density is 9.4 W / cm 2 , the substrate bias voltage is -115 V, the substrate temperature is 267 °C, the substrate rotation rate is 7 rpm, the deposition rate is 3.6 nm / min, the deposition time is 41 min, and the plasma density is 2.2×10 10 cm -3 , and the film thickness uniformity deviation ≤ ±3%.

[0069] S4. Then, annealing treatment and gradient cooling treatment are carried out to obtain the low sheet resistance and high transmittance ITO coating.

[0070] The process parameters of the annealing treatment include: continuously introducing a mixed gas of hydrogen and nitrogen, the volume flow of hydrogen accounts for 3.8% of the volume flow of the mixed gas, the total flow of the mixed gas is 590 sccm, the pressure in the furnace is 2 Torr, the heating rate is 7 °C / min, the constant temperature is 456 °C, the constant temperature time is 43 min, and the temperature fluctuation during constant temperature ≤ ±2 °C.

[0071] The process parameters of the gradient cooling treatment include: cooling from the annealing temperature to 200 °C at a rate of 3.3 °C / min in the first stage, and then cooling to room temperature at a rate of 1.3 °C / min in the second stage. The whole process maintains a nitrogen protection atmosphere with an oxygen content ≤ 1 ppm, and finally obtains a low sheet resistance and high transmittance ITO coating.

[0072] For the low sheet resistance and high transmittance ITO coating of this embodiment, the ITO coating is located on a yttrium-doped zirconia substrate; the ITO coating is an ITO(400) strong texture; the (400) crystal orientation of the ITO(400) strong texture is perpendicular to the surface of the yttrium-doped zirconia substrate; the ITO(400) strong texture has a columnar crystal morphology; the average lateral size of the columnar crystal grains is 115 nm; a coherent interface is formed between the yttrium-doped zirconia substrate and the low sheet resistance and high transmittance ITO coating; the proportion of 3° small-angle grain boundaries in the ITO coating is 76.0%, and the twin density is 3×10 5 cm-2.

[0073] Example 3:

[0074] A preparation method of a low sheet resistance and high transmittance ITO coating, comprising the following steps:

[0075] S1. Prepare a yttrium-doped zirconia substrate:

[0076] A clean Si(100) substrate with a surface roughness Ra ≤ 0.2 nm is placed in a multi-cathode sputtering deposition system. The system includes two DC sputtering sources and one RF sputtering source. The two DC sputtering sources and one RF sputtering source are arranged in a confocal manner and are at an angle of 61 degrees with the substrate normal. Among them, the two DC sputtering sources are used for reactive sputtering of zirconium targets, and the RF sputtering source is used for reactive sputtering of yttrium targets. By reactive co-sputtering two zirconium targets and one yttrium target, a yttrium-doped zirconia substrate is deposited in a mixed plasma of argon and oxygen, where the volume flow ratio of argon to oxygen is 1.8:1, the total working pressure is 10 mTorr, the power density of the zirconium target is 14 W / cm 2 , and the power density of the yttrium target is 2.3 W / cm 2 , the substrate bias voltage is -420 V, and the substrate temperature is 76 °C.

[0077] In the above yttrium-doped zirconia substrate, the (200) crystal orientation of the yttrium-doped zirconia is perpendicular to the surface of the yttrium-doped zirconia substrate; the root mean square roughness of the yttrium-doped zirconia substrate is 0.5 nm; the doping amount of yttrium oxide in the yttrium-doped zirconia substrate is 6.5 at.%.

[0078] The preparation method of the clean Si(100) substrate is as follows: The commercial Si(100) substrate is immersed in a hydrofluoric acid solution with a mass fraction of 4.2% for 8 min to remove the surface oxide layer, and then transferred to a mixed cleaning solution composed of deionized water, hydrogen peroxide with a mass fraction of 28%, and ammonia water with a mass fraction of 28% in a volume ratio of 5:1:1. It is ultrasonically treated at 81 °C for 16 min, and the ultrasonic frequency is 52 kHz. After the substrate is rinsed 4 times with ultrapure water, the surface residual liquid is blown off at a flow rate of 13 L / min in a nitrogen atmosphere, and finally placed in a vacuum oven and dried at 138 °C and -0.09 MPa for 48 min to obtain a clean Si(100) substrate with a surface roughness Ra ≤ 0.2 nm.

[0079] S2. Surface activation of the yttrium-doped zirconia substrate:

[0080] The yttrium-doped zirconia substrate is placed in a plasma cleaning chamber, and a mixed gas of argon and oxygen with a volume flow ratio of 1:1 is introduced. It is subjected to 13 min of RF plasma treatment under a power density of 0.8 W / cm 2 and a pressure of 8 mTorr.

[0081] S3. The surface-activated yttrium-doped zirconia substrate is placed in an RF magnetron sputtering chamber for magnetron sputtering to form an ITO film on the surface of the yttrium-doped zirconia substrate;

[0082] The process parameters of magnetron sputtering include: using a mixed gas of argon and oxygen as the working gas, where the volume flow ratio of oxygen to argon is 32:52, the total working pressure is 4.2 mTorr, using an ITO target, the SnO2 doping amount of the ITO target is 9.1 wt%, and the target power density is 10.3 W / cm 2 , the substrate bias voltage is -130 V, the temperature is 279 °C, the substrate rotation rate is 8 rpm, the deposition rate is 4.2 nm / min, the deposition time is 47 min, and the plasma density is 3.4×10 10 cm -3 , and the film thickness uniformity deviation ≤ ±3%.

[0083] S4. Then, annealing treatment and gradient cooling treatment are carried out to obtain the low sheet resistance and high light transmittance ITO coating film.

[0084] The process parameters of the annealing treatment include: continuously introducing a mixed gas of hydrogen and nitrogen, the volume flow of hydrogen accounts for 4.1% of the volume flow of the mixed gas, the total flow of the mixed gas is 680 sccm, the pressure in the furnace is 3 Torr, the heating rate is 8 °C / min, the constant temperature is 492 °C, the constant temperature time is 46 min, and the temperature fluctuation during the constant temperature period ≤ ±2 °C.

[0085] The process parameters of the gradient cooling treatment include: cooling from the annealing temperature to 200 °C at a rate of 3.6 °C / min in the first stage, and cooling to room temperature at a rate of 1.6 °C / min in the second stage. The nitrogen protection atmosphere is maintained throughout the process and the oxygen content ≤ 1 ppm, and finally the low sheet resistance and high light transmittance ITO coating film is obtained.

[0086] For the low sheet resistance and high light transmittance ITO coating film of this embodiment, the ITO coating film is located on a yttrium-doped zirconia substrate; the ITO coating film is ITO(400) strong texture; the (400) crystal orientation of the ITO(400) strong texture is perpendicular to the surface of the yttrium-doped zirconia substrate; the ITO(400) strong texture has a columnar crystal morphology; the average lateral size of the columnar crystal grains is 150 nm; a coherent interface is formed between the yttrium-doped zirconia substrate and the low sheet resistance and high light transmittance ITO coating film; the proportion of 5° small-angle grain boundaries in the ITO coating film is 85.0%, and the twin density is 1×10 5 cm-2.

[0087] Example 4:

[0088] A preparation method of a low sheet resistance and high light transmittance ITO coating film, comprising the following steps:

[0089] S1. Prepare a yttrium-doped zirconia substrate:

[0090] A clean Si(100) substrate with a surface roughness Ra ≤ 0.2 nm is placed in a multi-cathode sputtering deposition system, which includes two DC sputtering sources and one RF sputtering source. The two DC sputtering sources and one RF sputtering source are arranged in a confocal manner and at an angle of 65 degrees with the substrate normal. Among them, the two DC sputtering sources are used for reactive sputtering of zirconium targets, and the RF sputtering source is used for reactive sputtering of yttrium targets. By reactive co-sputtering two zirconium targets and one yttrium target, a yttrium-doped zirconia substrate is deposited in an argon-oxygen mixed plasma, where the volume flow ratio of argon to oxygen is 2.0:1, the total working pressure is 12 mTorr, the power density of the zirconium target is 15 W / cm 2 , and the power density of the yttrium target is 2.5 W / cm 2 , the substrate bias voltage is -500 V, and the substrate temperature is 80 °C.

[0091] In the above yttrium-doped zirconia substrate, the (200) crystal orientation of the yttrium-doped zirconia is perpendicular to the surface of the yttrium-doped zirconia substrate; the root mean square roughness of the yttrium-doped zirconia substrate is 0.4 nm; the doping amount of yttrium oxide in the yttrium-doped zirconia substrate is 8 at.%.

[0092] The preparation method of the clean Si(100) substrate is as follows: The commercial Si(100) substrate is immersed in a hydrofluoric acid solution with a mass fraction of 5.0% for 10 min to remove the surface oxide layer, and then transferred to a mixed cleaning solution composed of deionized water, hydrogen peroxide with a mass fraction of 30%, and ammonia water with a mass fraction of 30% in a volume ratio of 5:1:1, and ultrasonically treated at 85 °C for 20 min, with an ultrasonic frequency of 60 kHz. After the substrate is rinsed 5 times with ultrapure water, the surface residual liquid is blown off at a flow rate of 15 L / min in a nitrogen atmosphere, and finally placed in a vacuum oven and dried at 150 °C and -0.1 MPa for 60 min to obtain a clean Si(100) substrate with a surface roughness Ra ≤ 0.2 nm.

[0093] S2. Surface activation of the yttrium-doped zirconia substrate:

[0094] The yttrium-doped zirconia substrate is placed in a plasma cleaning chamber, and a mixed gas of argon and oxygen with a volume ratio of 1:1 is introduced, and RF plasma treatment is carried out for 15 min under the conditions of a power density of 1.0 W / cm 2 and a pressure of 10 mTorr.

[0095] S3. The surface-activated yttrium-doped zirconia substrate is placed in an RF magnetron sputtering chamber for magnetron sputtering to form an ITO film on the surface of the yttrium-doped zirconia substrate;

[0096] The process parameters of magnetron sputtering include: using a mixed gas of argon and oxygen as the working gas, where the volume flow ratio of oxygen to argon is 40:60, the total working pressure is 5.0 mTorr, the SnO2 doping amount of the ITO target is 9.5 wt%, and the target power density is 11.5 W / cm 2 , the substrate bias voltage is -150 V, the substrate temperature is 295 °C, the substrate rotation rate is 10 rpm, the deposition rate is 5.0 nm / min, the deposition time is 55 min, and the plasma density is 5×10 10 cm -3 , and the film thickness uniformity deviation is ≤±3%.

[0097] S4. Then, annealing treatment and gradient cooling treatment are carried out to obtain the low sheet resistance and high transmittance ITO coating film.

[0098] The process parameters of the annealing treatment include: continuously introducing a mixed gas of hydrogen and nitrogen, the volume flow of hydrogen accounts for 4.5% of the volume flow of the mixed gas, the total flow of the mixed gas is 800 sccm, the pressure in the furnace is 5 Torr, the heating rate is 9 °C / min, the constant temperature is 540 °C, the constant temperature time is 50 min, and the temperature fluctuation during the constant temperature period is ≤±2 °C.

[0099] The process parameters of the gradient cooling treatment include: cooling from the annealing temperature to 200 °C at a rate of 4 °C / min in the first stage, and then cooling to room temperature at a rate of 2 °C / min in the second stage. The whole process maintains a nitrogen protection atmosphere with an oxygen content of ≤1 ppm, and finally obtains a low sheet resistance and high transmittance ITO coating film.

[0100] For the low sheet resistance and high transmittance ITO coating film of this embodiment, the ITO coating film is located on a yttrium-doped zirconia substrate; the ITO coating film is an ITO(400) strong texture; the (400) crystal orientation of the ITO(400) strong texture is perpendicular to the surface of the yttrium-doped zirconia substrate; the ITO(400) strong texture has a columnar crystal morphology; the average lateral size of the columnar crystal grains is 130 nm; a coherent interface is formed between the yttrium-doped zirconia substrate and the low sheet resistance and high transmittance ITO coating film; the proportion of 4° small-angle grain boundaries in the ITO coating film is 80.0%, and the twin density is 2.2×10 6 cm-2.

[0101] Comparative Example 1:

[0102] It is basically the same as Example 1, except that a common non-oriented Si substrate is used to replace the commercial Si(100) substrate.

[0103] In comparison, Figure 5XRD phase analysis diagram of the ITO coating in Comparative Example 1. The results show that neither ITO nor YSZ grown on a common non-oriented Si substrate forms a strong texture, indicating that the orientation of the substrate has an important influence on the crystallization of the ITO film.

[0104] Comparative Example 2:

[0105] Basically the same as Example 1, except that the root mean square roughness of the yttria-stabilized zirconia substrate is 2.0 nm;

[0106] The preparation method of the yttria-stabilized zirconia substrate in this comparative example is as follows: Place a clean Si(100) substrate in a multi-cathode sputtering deposition system, which includes two DC sputtering sources and one RF sputtering source. The two DC sputtering sources and one RF sputtering source are arranged in a confocal manner and are at an angle of 55 degrees with the substrate normal. Among them, the two DC sputtering sources are used for reactive sputtering of zirconium targets, and the RF sputtering source is used for reactive sputtering of yttrium targets. By reactive co-sputtering two zirconium targets and one yttrium target, deposit the yttria-stabilized zirconia substrate in an argon-oxygen mixed plasma, where the volume flow ratio of argon to oxygen is 1.5:1, the total working pressure is 20 mTorr, the power density of the zirconium target is 12 W / cm 2 , and the power density of the yttrium target is 2.0 W / cm 2 , the substrate bias voltage is -100 V, and the substrate temperature is 50 °C.

[0107] In addition, Figure 6 The surface roughness measurement results of the yttria-stabilized zirconia substrate in Comparative Example 2 show that the roughness reaches 2 nm, which is much higher than that in Example 1, indicating that the surface quality of the substrate is poor and may affect the growth uniformity and electrical properties of the ITO film. The above results fully prove that the present invention successfully prepares an ITO coating with low sheet resistance and high transmittance by optimizing the substrate orientation, surface quality and deposition process, and is significantly superior to the comparative example scheme.

[0108] Comparative Example 3:

[0109] Basically the same as Example 1, except that the yttria-stabilized zirconia substrate is polycrystalline with no obvious preferred orientation. The preparation method of the yttria-stabilized zirconia substrate in this comparative example is as follows: Place a clean Si(100) substrate in a multi-cathode sputtering deposition system, which includes two DC sputtering sources and one RF sputtering source. The two DC sputtering sources and one RF sputtering source are arranged in a confocal manner and are at an angle of 55 degrees with the substrate normal. Among them, the two DC sputtering sources are used for reactive sputtering of zirconium targets, and the RF sputtering source is used for reactive sputtering of yttrium targets. By reactive co-sputtering two zirconium targets and one yttrium target, deposit the yttria-stabilized zirconia substrate in an argon-oxygen mixed plasma, where the volume flow ratio of argon to oxygen is 3.5:1, the total working pressure is 8 mTorr, the power density of the zirconium target is 12 W / cm 2 , and the power density of the yttrium target is 2.0 W / cm2 , the substrate bias voltage is -50V and the substrate temperature is 70°C.

[0110] Comparative Example 4:

[0111] It is basically the same as Example 1, except that the surface of the yttrium-doped zirconia substrate is not subjected to activation treatment.

[0112] Comparative Example 5:

[0113] It is basically the same as Example 1, except that the substrate bias voltage in the process parameters of magnetron sputtering is -50V.

[0114] Comparative Example 6:

[0115] It is basically the same as Example 1, except that the constant temperature in the process parameters of annealing treatment is 350°C.

[0116] Comparative Example 7:

[0117] It is basically the same as Example 1, except that in the process parameters of gradient cooling, it is cooled to 200°C at a rate of 6°C / min in the first stage.

[0118] Performance test:

[0119] Sheet resistance test: A four-probe tester (Keithley 2400 series) is used to measure the sheet resistance values at different positions. With a fixed probe spacing, a constant current is applied and the voltage drop is measured, and the sheet resistance is calculated according to the formula Rs = (V / I) × (π / ln2).

[0120] Transmittance test: The transmittance test uses a UV-Vis spectrophotometer (such as PerkinElmer Lambda950) to measure the transmission spectrum of the ITO film under an air background. To avoid the influence of the yttrium-doped zirconia substrate (YSZ substrate) on the test results, the ITO film can be separated by chemical etching method. The chemical etching method uses BOE (HF:NH4F = 1:10) solution to etch the YSZ substrate, so that the ITO is released and transferred to a quartz substrate; after peeling, the sample is fixed on an optical bracket, the light beam is vertically irradiated on the ITO film, and the background is corrected with air. The test range is set to 300 - 800nm, and the transmittance data is recorded step by step at 1nm intervals, focusing on the transmittance at 550nm and the average transmittance in the range of 380 - 780nm.

[0121] Adhesion test: A progressive load scratch experiment is carried out using a scratch tester (such as AntonPaar Revetest), and the critical load for film peeling is recorded.

[0122] The performance data of the ITO coatings in Examples 1 - 4 and Comparative Examples 1 - 7 are summarized in Table 1.

[0123] Table 1 Performance data of ITO coatings for Examples 1-4 and Comparative Examples 1-7

[0124]

[0125]

[0126] As can be seen from Table 1, ordinary non-oriented Si substrates may cause a decrease in the crystallization quality of ITO, resulting in an increase in sheet resistance, a decrease in light transmittance, and a decrease in adhesion. An increase in substrate roughness to 2.0 nm may affect the crystallization quality of ITO, increasing the sheet resistance, decreasing the light transmittance, and decreasing the adhesion. The polycrystalline YSZ substrate without preferred orientation may affect the crystallization quality of ITO, resulting in a significant increase in sheet resistance, a decrease in light transmittance, and a decrease in adhesion. Failure to perform substrate surface activation treatment may reduce the adhesion of ITO, causing a significant decrease in adhesion, while affecting the crystallization quality of ITO and resulting in an increase in sheet resistance. A reduction in substrate bias voltage to -50 V may cause a decrease in ITO particle size, affecting carrier transport, slightly increasing the sheet resistance, decreasing the light transmittance, and slightly decreasing the adhesion. A reduction in the annealing temperature to 350 °C may result in incomplete crystallization of ITO, affecting the conductivity, slightly increasing the sheet resistance, decreasing the light transmittance, and decreasing the adhesion. Adjusting the cooling rate to 6 °C / min may cause stress accumulation, affecting the ITO structure, slightly increasing the sheet resistance, decreasing the light transmittance, and slightly decreasing the adhesion.

[0127] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that any equivalent structural transformation made under the concept of the present invention using the content of the specification and drawings of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A method for preparing a low-resistance and high-transmittance ITO coating, characterized in that: The following steps are involved: S1. preparing a yttrium-doped zirconia substrate having a root mean square roughness of 0.2 to 0.5 nm; S2, performing surface activation on the yttrium-doped zirconium oxide substrate; S3, placing the surface activated yttrium-doped zirconia substrate into a radio frequency magnetron sputtering chamber for magnetron sputtering to form an ITO film on the surface of the yttrium-doped zirconia substrate; S4, then perform annealing treatment and gradient cooling treatment to obtain the low-square-resistance and high-transmittance ITO coating.

2. The method for preparing a low-resistance and high-transmittance ITO coating according to claim 1, characterized in that: In the yttrium-doped zirconia substrate, the (200) crystal orientation of the yttrium-doped zirconia is perpendicular to the surface of the yttrium-doped zirconia substrate; and the doping amount of yttrium oxide in the yttrium-doped zirconia substrate is 4-8 at.%.

3. A method for preparing a low-resistance and high-transmittance ITO coating as claimed in claim 1 or 2, characterized in that: The method for preparing the yttrium-doped zirconium oxide substrate comprises the following steps: A clean Si (100) substrate with a surface roughness of Ra≤0.2 nm is placed in a multi-cathode sputtering deposition system, wherein two DC sputtering sources and one RF sputtering source of the multi-cathode sputtering deposition system are arranged in a confocal manner and form an angle of 55 to 65 degrees with the substrate normal, wherein the two DC sputtering sources are used for reactive sputtering of zirconium targets, and the RF sputtering source is used for reactive sputtering of yttrium targets, and a yttrium-doped zirconium oxide substrate is deposited in an argon and oxygen mixed plasma by reactive co-sputtering of two zirconium targets and one yttrium target, wherein the volume flow ratio of argon to oxygen is 1.5 to 2.0:1, the total working pressure is 8 to 12 mTorr, and the power density of the zirconium target is 12 to 15 W / cm 2 , the power density of the yttrium target is 2.0~2.5W / cm 2 , the substrate bias is -300~-500V, and the substrate temperature is 70~80℃.

4. The method for preparing a low-resistance and high-transmittance ITO coating according to claim 3, characterized in that: The preparation method of the clean Si (100) substrate comprises the following steps: placing the Si (100) substrate in a hydrofluoric acid solution with a mass fraction of 3.0-5.0% to soak the surface oxide layer, then transferring the Si (100) substrate to a mixed cleaning solution composed of deionized water, hydrogen peroxide with a mass fraction of 25-30% and ammonia water with a mass fraction of 25-30% in a volume ratio of 5:1:1, ultrasonically treating the substrate at 75-85° C. for 10-20 minutes with an ultrasonic frequency of 40-60 kHz, then rinsing the substrate with ultrapure water, blowing off residual liquid on the surface in a nitrogen atmosphere, and finally drying the substrate in a vacuum oven to obtain the substrate.

5. The method for preparing a low-resistance and high-transmittance ITO coating according to claim 1, characterized in that: The surface activation of the yttrium-doped zirconia substrate comprises the following steps: placing the yttrium-doped zirconia substrate in a plasma cleaning chamber, introducing a mixed gas of argon and oxygen with a volume flow ratio of 1:1, and performing surface activation at a power density of 0.5 to 1.0 W / cm 2 , and perform RF plasma treatment for 10 to 15 minutes at a pressure of 5 to 10 mTorr.

6. The method for preparing a low-resistance and high-transmittance ITO coating according to claim 1, characterized in that: The process parameters of the magnetron sputtering include: using a mixed gas of argon and oxygen as the working gas, wherein the volume flow ratio of oxygen to argon is 20-40:40-60, the total working pressure is 3.0-5.0 mTorr, using an ITO target material, the content of SnO2 in the ITO target material is 8.5-9.5wt%, and the power density of the target material is 8.5-11.5 W / cm 2 , substrate bias voltage is -100~-150V, substrate temperature is 255~295℃, substrate rotation rate is 5~10rpm, deposition rate is 3.0~5.0nm / min, deposition time is 35~55min, plasma density is 1×10 10 ~5×10 10 cm -3 , film thickness uniformity deviation ≤±3%.

7. The method for preparing a low-resistance and high-transmittance ITO coating according to claim 1, characterized in that: The process parameters of the annealing treatment include: continuously introducing a mixed gas of hydrogen and nitrogen, the volume flow rate of hydrogen accounting for 3.5-4.5% of the volume flow rate of the mixed gas, the pressure in the annealing furnace is 1-5 Torr, the heating rate is 6-9°C / min, the constant temperature is 420-540°C, the constant temperature time is 40-50min, and the temperature fluctuation during the constant temperature period is ≤±2°C.

8. The method for preparing a low-resistance and high-transmittance ITO coating according to claim 1, characterized in that: The process parameters of the gradient cooling treatment include: cooling from the annealing temperature to 200-230°C at a rate of 3-4°C / min in the first stage, cooling to room temperature at a rate of 1-2°C / min in the second stage, maintaining a nitrogen protective atmosphere throughout the process and an oxygen content of ≤1ppm.

9. A low-resistance and high-transmittance ITO coating film prepared by the method for preparing a low-resistance and high-transmittance ITO coating film as described in any one of claims 1 to 8, wherein the low-resistance and high-transmittance ITO coating film is located on an yttrium-doped zirconia substrate; the low-resistance and high-transmittance ITO coating film is an ITO (400) strong texture; the (400) crystal direction of the ITO (400) strong texture is perpendicular to the surface of the yttrium-doped zirconia substrate; and the ITO (400) strong texture presents a columnar crystal morphology, and the average lateral size of the columnar crystal grains is 100 to 150 nm.

10. The low-resistance and high-transmittance ITO coating according to claim 9, characterized in that: A coherent interface is formed between the yttrium-doped zirconia substrate and the low-square-resistance and high-transmittance ITO coating; The low square resistance and high light transmittance ITO coating has a 2-5° small angle grain boundary ratio of 72.0-85.0% and a twin density of 10 5 ~4.5×10 6 cm-2.

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