Preparation method of transparent conductive oxide film
By forming a metal layer on the substrate under oxygen-free conditions and oxidizing to form a metal oxide film, the damage problem of oxygen negative ions on the substrate is solved, the device performance is improved and the consistency of the film structure is maintained.
Patent Information
- Application Number
- CN202411912438.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-23
- Publication Date
- 2025-03-28
AI Technical Summary
When preparing transparent conductive oxide films, the substrate surface is susceptible to bombardment by negative oxygen ions, causing damage and affecting device performance.
A metal layer is formed on the substrate under an oxygen-free condition, and a first metal oxide layer is formed on the side of the metal layer away from the substrate, and the metal layer is then oxidized to form a second metal oxide layer to form a metal oxide film including the first metal oxide layer and the second metal oxide layer.
By forming a metal layer as a substrate protective layer under oxygen-free conditions, the bombardment of oxygen negative ions on the substrate is avoided, and the device performance is improved. By forming a second metal oxide layer, the consistency of the film structure is ensured and the performance is avoided.
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Figure CN119730486A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and in particular to a method for preparing a transparent conductive oxide film. Background Art
[0002] Transparent conductive oxide films have good visible light transmittance and conductivity. They have been widely used in the optoelectronic field. They are usually used as transparent electrodes to connect light-emitting units with metal electrodes in light-emitting devices. Magnetron sputtering is one of the most widely used processes for depositing transparent conductive films. When magnetron sputtering is used to deposit transparent conductive films (ITO, indium tin oxide), oxygen in the ITO target or oxygen in the chamber reaction gas will form oxygen anions after particles collide with each other. The oxygen anions bombard the substrate surface under the action of a high-voltage electric field. Due to the high speed and mass of the oxygen anions, irreparable damage is formed on the substrate surface, which in turn affects the device performance. Summary of the invention
[0003] In view of the shortcomings of the related art, the present application proposes a method for preparing a transparent conductive oxide film to solve the problem that the substrate surface is easily damaged by oxygen negative ion bombardment when preparing the transparent conductive oxide film in the related art.
[0004] The present invention provides a method for preparing a transparent conductive oxide film, comprising the following steps:
[0005] Under oxygen-free conditions, a metal layer is formed on the substrate;
[0006] A first metal oxide layer is formed on a side of the metal layer away from the substrate, and the metal layer is oxidized to form a second metal oxide layer, so as to form a metal oxide film including the first metal oxide layer and the second metal oxide layer; the material of the first metal oxide layer is the same as that of the second metal oxide layer.
[0007] In some embodiments, the step of forming a first metal oxide layer on a side of the metal layer away from the substrate and oxidizing the metal layer to form a second metal oxide layer is performed in a reaction chamber; the step of forming the first metal oxide layer on a side of the metal layer away from the substrate and oxidizing the metal layer to form a second metal oxide layer comprises:
[0008] Oxidizing the metal layer to form a second metal oxide layer under a first power and a first gas environment, wherein the gas in the reaction chamber under the first gas environment includes oxygen;
[0009] The first metal oxide layer is formed on the second metal oxide layer under a second power and a second gas environment; wherein the first power is greater than the second power.
[0010] In some embodiments, the first power ranges from 800W to 1500W.
[0011] In some embodiments, the gas in the reaction chamber under the first gas environment and the second gas environment includes oxygen and process gas, and the process gas includes at least one of inert gases; the proportion of oxygen in the reaction chamber under the first gas environment is a first proportion, and the proportion of oxygen in the reaction chamber under the second gas environment is a second proportion, and the first proportion is greater than the second proportion;
[0012] Alternatively, the gas in the reaction chamber under the second gas environment does not include oxygen.
[0013] In some embodiments, under the first gas environment, the gas flow ratio of the process gas to oxygen in the reaction chamber ranges from 50:1 to 10:1; under the second gas environment, when the gas in the chamber includes oxygen, the gas flow ratio of the process gas to oxygen is greater than 95:5.
[0014] In some embodiments, forming a first metal oxide layer on a side of the metal layer away from the substrate, and oxidizing the metal layer to form a second metal oxide layer comprises:
[0015] forming the first metal oxide layer on a side of the metal layer away from the substrate to obtain a composite layer including the metal layer and the first metal oxide layer;
[0016] The composite layer is heat-treated to diffuse oxygen ions in the first metal oxide layer into the metal layer, and the metal layer is transformed into a second metal oxide layer.
[0017] In some embodiments, heat treating the composite layer comprises:
[0018] The composite layer is heat treated by an annealing process.
[0019] In some embodiments, in a direction from the substrate to the metal layer, a thickness of the metal layer is less than one tenth of a thickness of the first metal oxide layer.
[0020] In some embodiments, the metal layer includes at least one of indium, tin, aluminum, zinc, gallium, strontium, and titanium.
[0021] In some embodiments, in a direction from the substrate to the metal layer, the thickness of the metal layer is less than 10 nanometers.
[0022] The beneficial effects of this application include:
[0023] The present application is carried out under oxygen-free conditions, so in the process of preparing the metal layer, it is possible to avoid the formation of oxygen anions in the reaction chamber to bombard the substrate surface and cause damage. Furthermore, a metal layer is first formed on the substrate surface as a substrate protection layer, and then in the process of forming the first metal oxide layer, the metal layer can be used to withstand the bombardment of oxygen anions, protect the substrate surface from the bombardment of oxygen anions, and improve the device performance. Furthermore, in step S200 of this embodiment, the metal layer is further oxidized into a second metal oxide layer, and the second metal oxide layer and the first metal oxide layer can together constitute a metal oxide film, and since the material of the first metal oxide layer and the material of the second metal oxide layer are the same, it can be achieved that the metal oxide film prepared in this embodiment is consistent with the metal oxide film formed by magnetron sputtering directly on the substrate in a single step, and thus does not affect the device performance.
[0024] Additional aspects and advantages of the present application will be partially given in the following description, which will become apparent from the following description, or will be understood through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS
[0025] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.
[0026] Figure 1 The figure shows a schematic structural diagram of a device for preparing a transparent conductive oxide film in the related art;
[0027] Figure 2 Shown is a schematic diagram of the process of preparing a transparent conductive oxide film provided by the present application;
[0028] Figure 3 Shown is a schematic structural diagram of an intermediate structure obtained in a method for preparing a transparent conductive oxide thin film provided by an exemplary embodiment of the present application;
[0029] Figure 4 Shown is a schematic structural diagram of a final structure obtained in a method for preparing a transparent conductive oxide thin film provided by an exemplary embodiment of the present application;
[0030] Figure 5 Shown is a schematic structural diagram of an intermediate structure obtained in a method for preparing a transparent conductive oxide thin film provided by an exemplary embodiment of the present application;
[0031] Figure 6 Shown is a schematic structural diagram of an intermediate structure obtained in a method for preparing a transparent conductive oxide film provided by an exemplary embodiment of the present application. DETAILED DESCRIPTION
[0032] ITO targets are usually made by sintering a mixture of indium oxide and tin oxide. Figure 1 As shown, during the magnetron sputtering process, the ITO target is mounted on the cathode of the magnetron sputtering equipment, and a certain distance is ensured between the ITO target and the substrate. Oxygen and argon are introduced, a direct current power supply (DC) or a radio frequency power supply (RF) is started, and a high voltage (usually several hundred volts to several thousand volts) is applied to the ITO target. Under the action of the high-voltage electric field, the argon gas is ionized into plasma, and the argon ions bombard the surface of the target material, splashing out the atoms or molecules in the target material, which is called sputtering. The sputtered indium atoms and tin atoms combine with the oxygen in the ITO target material or the oxygen in the chamber reaction gas to form indium tin oxide, which is deposited on the substrate to form an ITO film. However, when preparing ITO thin films by magnetron sputtering, a higher voltage is usually used to maintain the efficiency of target atom sputtering. However, the oxygen in the ITO target material or the oxygen in the chamber reaction gas will form oxygen anions after the particles collide with each other. The oxygen anions bombard the substrate surface under the action of the high-voltage electric field. Due to the large speed and mass of the oxygen anions, the substrate surface is damaged beyond repair, thereby affecting the device performance. When the substrate is P-type GaN, the contact resistance between the substrate and the ITO film will be further increased.
[0033] The method for preparing a transparent conductive oxide film provided in the present application is intended to solve the above technical problems.
[0034] The following is a detailed description of the method for preparing the transparent conductive oxide film in the embodiment of the present application in conjunction with the accompanying drawings. In the absence of conflict, the features in the following embodiments can complement or be combined with each other.
[0035] The present application provides a method for preparing a transparent conductive oxide film. Figure 2 As shown, the following steps are included:
[0036] S100: forming a metal layer on the substrate under oxygen-free conditions;
[0037] Through step S100, the following can be obtained: Figure 3 The first intermediate structure is shown.
[0038] S200: forming a first metal oxide layer on a side of the metal layer away from the substrate, and oxidizing the metal layer to form a second metal oxide layer, so as to form a metal oxide thin film including the first metal oxide layer and the second metal oxide layer; the material of the first metal oxide layer is the same as the material of the second metal oxide layer.
[0039] Through step S200, the following can be obtained: Figure 4 The final structure is shown.
[0040] In this embodiment, step S100 is performed under oxygen-free conditions, so in the process of preparing the metal layer, it is possible to avoid the formation of oxygen anions in the reaction chamber to bombard the substrate surface and cause damage. Furthermore, in step S200, a metal layer is first formed on the substrate surface as a substrate protection layer, and then in the process of forming the first metal oxide layer, the metal layer can be used to withstand the bombardment of oxygen anions, protect the substrate surface from the bombardment of oxygen anions, and improve the device performance. Furthermore, in step S200 of this embodiment, the metal layer is further oxidized into a second metal oxide layer, and the second metal oxide layer and the first metal oxide layer can together constitute a metal oxide film, and because the material of the first metal oxide layer and the material of the second metal oxide layer are the same, it can be achieved that the metal oxide film prepared by the two steps of step S100 and step S200 in this embodiment is consistent with the structure composition of the metal oxide film formed directly on the substrate by magnetron sputtering in a single step, and thus does not affect the device performance.
[0041] In some embodiments, the material of the substrate is p-GaN (p-type gallium nitride), and the substrate can be used as a partial component structure of the light-emitting unit in the LED device. The transparent conductive oxide film can be an indium tin oxide film (ITO), and the transparent conductive oxide film can be used as a transparent electrode of the LED, which can further reduce the contact resistance between the light-emitting unit and the transparent electrode in the LED device, improve the injection efficiency of the current between ITO and P-GaN, make the current more evenly distributed in the P-GaN layer, and reduce local overheating and current crowding. It can also reduce the operating temperature and power consumption of the LED device, further extending the service life of the LED device. And because the transparent conductive oxide film finally formed will not affect the transmittance of the light-emitting unit.
[0042] The specific implementation of the method for preparing the transparent conductive oxide film provided in the embodiment of the present application is described in detail below.
[0043] Implementation Method 1
[0044] In step S100, the step of forming a metal layer on the substrate under oxygen-free conditions is performed in a reaction chamber of a magnetron sputtering device, specifically comprising the following steps:
[0045] Step S110: installing a metal target on a cathode of a magnetron sputtering device, and ensuring that there is a certain distance between the metal target and the substrate;
[0046] Step S120: introducing a process gas into the reaction chamber, wherein the process gas includes at least one of inert gases;
[0047] Step S130: starting a DC power supply or a radio frequency power supply, applying high voltage to the metal target, bombarding the surface of the metal target with process gas, sputtering out metal atoms in the metal target, and depositing them on the substrate to form a metal layer.
[0048] Through steps S110, S120 and S130, the following can be obtained: Figure 3 The first intermediate structure is shown.
[0049] In this embodiment, a metal layer is formed on a substrate by magnetron sputtering, and the preparation process is mature and the method is simple. Since step S100 is performed under oxygen-free conditions and a metal target material is used as a raw material, during the magnetron sputtering process, no oxygen negative ions are formed in the reaction chamber to bombard the substrate surface and cause damage to the substrate surface. The metal layer can also be used as a substrate protective layer in subsequent processes to protect the substrate surface from damage.
[0050] In some embodiments, the material of the metal target in step S110 includes at least one of indium, tin, aluminum, zinc, gallium, strontium and titanium. Preferably, the metal target includes an indium-tin alloy. Further, the ratio of indium to tin ranges from 85:15 to 95:5. Further preferably, the ratio of indium to tin is 9:1.
[0051] In some embodiments, the process gas in step S120 may include at least one of argon, nitrogen and helium. Preferably, the process gas is argon.
[0052] In some embodiments, the power of the high voltage applied in step S130 ranges from 80 W (watts) to 300 W (watts).
[0053] In some embodiments, the step of forming a metal oxide layer on a side of the metal layer away from the substrate and oxidizing the metal layer to form a second metal oxide layer in step S200 is performed in a reaction chamber; step S200 specifically includes the following steps:
[0054] Step S210: Oxidizing the metal layer to form a second metal oxide layer under a first power and a first gas environment, wherein the gas in the reaction chamber under the first gas environment includes oxygen.
[0055] Through step S210, the following can be obtained: Figure 5 The second intermediate structure is shown.
[0056] Step S220: forming a first metal oxide layer on the second metal oxide layer under a second power and a second gas environment; wherein the first power is greater than the second power.
[0057] Through step S220, the following can be obtained: Figure 4 The final structure is shown.
[0058] In this embodiment, a reaction is first performed in a reaction chamber under aerobic conditions using a relatively large first power. Then, the oxygen anions after the oxygen in the chamber is converted bombard the metal layer under relatively large power conditions to inject oxygen into the metal layer, causing the metal layer to oxidize to form a second metal oxide layer. After the first metal oxide layer is formed on the side of the second metal oxide layer away from the substrate, the first metal oxide layer and the second metal oxide layer can together form a whole layer of metal oxide film directly in contact with the substrate, which can prevent the substrate from being damaged by the bombardment of oxygen anions, reduce the contact resistance between the substrate and the transparent conductive oxide film, and when the substrate is a hungry component of the light-emitting unit, the current injection efficiency of the light-emitting unit can be improved, and the power consumption of the device can be reduced.
[0059] In some embodiments, the first power in step S210 ranges from 800 W to 1500 W. Setting a higher power is more conducive to improving ion implantation efficiency.
[0060] In some embodiments, the first power in step S220 ranges from 80W to 300W.
[0061] In some embodiments, in the direction from the substrate to the metal layer, the thickness of the metal layer in step S210 is less than 10 nanometers, so as to ensure that the metal layer is fully oxidized after being bombarded by oxygen anions in step S210. In some embodiments, the thickness of the metal layer can be 9 nm, 8 nm, 7 nm, 6 nm, 5 nm, 4 nm, 3 nm, 2 nm or 1 nm.
[0062] In some embodiments, the gases in the reaction chamber under the first gas environment and the second gas environment in step S210 and step S220 include oxygen and process gas, and the process gas includes at least one of the inert gases; the proportion of oxygen in the reaction chamber under the first gas environment is a first ratio, and the proportion of oxygen in the reaction chamber under the second gas environment is a second ratio, and the first ratio is greater than the second ratio.
[0063] In this embodiment, the oxygen content in the first gas environment in step S210 is relatively high, which can provide more oxygen anions to be injected into the metal layer to oxidize the metal layer into a second metal oxide layer. In step S220, the oxygen content in the second gas environment is relatively low, and the oxygen in the reaction chamber and the oxygen in the metal oxide target can be used together as raw materials for the oxygen element in the metal oxide film formed in the reaction.
[0064] In some embodiments, the gas in the reaction chamber under the second gas environment in step S220 does not include oxygen. In this embodiment, oxygen may not be introduced in step S220, and a metal oxide target is used as a source of oxygen in the metal oxide film.
[0065] In some embodiments, under the first gas environment, the gas flow ratio of the process gas to oxygen in the reaction chamber ranges from 50:1 to 10:1; under the second gas environment, when the gas in the chamber includes oxygen, the gas flow ratio of the process gas to oxygen is greater than 95:5. Further, under the first gas environment, the gas flow ratio of the process gas to oxygen in the reaction chamber may be 50:1, 40:1, 30:1, 20:1 or 10:1. Under the second gas environment, the gas flow ratio of the process gas to oxygen in the reaction chamber may be 96:4, 97:3, 98:2 or 99:1.
[0066] In some embodiments, the material of the metal oxide film includes zinc oxide (ZnO), tin oxide (SnO2), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium zinc oxide (IZO), strontium titanate (STO), etc.
[0067] In some embodiments, step S210: oxidizing the metal layer to form a second metal oxide layer under a first power and a first gas environment specifically includes the following steps:
[0068] Step S211: introducing process gas and oxygen into the reaction chamber, wherein the process gas includes at least one of inert gases; and a gas flow ratio of the process gas to oxygen is in a range of 50:1 to 10:1;
[0069] Step S212: Start the DC power supply or the RF power supply at a power of 800W to 1500W. The process gas and oxygen are ionized under high voltage to form plasma. The plasma strikes the oxygen molecules to dissociate them and generate oxygen anions. When a metal oxide target is used, the oxygen atoms or oxygen molecules in the metal oxide target are sputtered out to form oxygen anions. The oxygen anions are bombarded and injected into the metal layer under high pressure, so that the metal layer is oxidized to form a second metal oxide layer.
[0070] Through step S211 and step S212, the following can be obtained: Figure 5 The second intermediate structure is shown.
[0071] In some embodiments, step S220: forming a first metal oxide layer on the second metal oxide layer under the second power and second gas environment specifically comprises the following steps:
[0072] Step S221: introducing process gas and oxygen into the reaction chamber, wherein the process gas includes at least one of inert gases; and a gas flow ratio of the process gas to oxygen is greater than 95:5.
[0073] Step S222: Start the DC power supply or the RF power supply, and apply high voltage to the target at a power of 80W to 300W. When the target is a metal oxide target, the process gas bombards the surface of the target, sputters out the metal atoms and oxygen atoms in the target, and the metal atoms combine with the oxygen in the reaction chamber or the oxygen in the target to form metal oxides, which are deposited on the substrate to form a first metal oxide layer. When the target is a metal target, the process gas bombards the surface of the target, sputters out the metal atoms in the target, and the metal atoms combine with the oxygen in the reaction chamber to form metal oxides, which are deposited on the substrate to form a first metal oxide layer.
[0074] Through steps S221 and S222, the following can be obtained: Figure 4 The final structure is shown.
[0075] In some other embodiments, step S220: forming a first metal oxide layer on the second metal oxide layer under the second power and second gas environment specifically comprises the following steps:
[0076] Step S221 ′: introducing a process gas into the reaction chamber, wherein the process gas includes at least one of inert gases.
[0077] Step S222': Start the DC power supply or the RF power supply, and apply high voltage to the metal oxide target at a power of 80 W to 300 W. The process gas bombards the surface of the target, sputters out the metal atoms and oxygen atoms in the target, and the metal atoms and oxygen in the target combine to form metal oxides, which are deposited on the substrate to form a first metal oxide layer.
[0078] Through steps S221' and S222', the following can be obtained: Figure 4 The final structure is shown.
[0079] Implementation Method 2
[0080] In the second embodiment, only the differences from the first embodiment are introduced, and the similarities are not repeated.
[0081] In this embodiment, when forming Figure 3 The first intermediate structure shown and the formation of Figure 3 The steps before the first intermediate structure shown are the same as those in the first embodiment. That is, step 100 in this embodiment is the same as step 100 in the first embodiment, and the difference lies in step 200. The details are as follows:
[0082] In this embodiment, the Figure 3 After the first intermediate structure shown, Figure 3 and Figure 6 As shown, the preparation method further includes step 200', which is specifically the following steps:
[0083] Step 210': forming a first metal oxide layer on a side of the metal layer away from the substrate to obtain a composite layer including the metal layer and the first metal oxide layer;
[0084] Through step 210', the following can be obtained: Figure 6 The third intermediate structure is shown.
[0085] Step 220 ′: heat-treating the composite layer to diffuse oxygen ions in the first metal oxide layer into the metal layer, so that the metal layer is transformed into a second metal oxide layer.
[0086] Through step 220', the following can be obtained: Figure 4 The final structure is shown.
[0087] In this embodiment, the metal layer can be transformed into a second metal oxide layer through a heat treatment process. The second metal oxide layer and the first metal oxide layer together constitute a metal oxide film, which can further make the oxygen ion distribution in the finally formed metal oxide film more uniform, reduce defects and unevenness in the material, thereby reducing resistivity and improving conductivity. In addition, scattering centers can be reduced and the transparency of the material can be improved. Since the oxygen ion distribution is more uniform, microscopic defects in the material can also be reduced, and mechanical strength and toughness can be improved.
[0088] In some embodiments, heat treating the composite layer in step 220' includes:
[0089] The composite layer is heat treated by an annealing process.
[0090] In this embodiment, an annealing process can be used to diffuse oxygen atoms or oxygen molecules in the first metal oxide layer into the metal layer to oxidize the metal layer into a second metal oxide layer. Furthermore, the annealing process can be a high temperature annealing process or a laser annealing process.
[0091] Furthermore, in this embodiment, the annealing process is used to heat treat the composite layer, specifically including:
[0092] The composite layer is heated at 450°C to 600°C for 3 to 20 minutes.
[0093] In some embodiments, in the direction from the substrate to the metal layer, the thickness of the metal layer is less than one tenth of the thickness of the first metal oxide layer. In this embodiment, when the thickness of the metal layer is small, when part of the oxygen element in the first metal oxide layer diffuses into the metal layer, the proportion of the oxygen element in the first metal oxide layer changes slightly, so after the composite layer is heat treated, the first metal oxide layer is less affected, so as to ensure that the distribution of the oxygen element in the metal oxide film is more uniform and the distribution ratio is less different from the ratio of the metal oxide film formed directly on the substrate.
[0094] In some embodiments, the material of the metal oxide film includes zinc oxide (ZnO), tin oxide (SnO2), indium tin oxide (ITO), aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), indium zinc oxide (IZO), strontium titanate (STO), etc.
[0095] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.
Claims
1. A method for preparing a transparent conductive oxide film, characterized in that: include: Under oxygen-free conditions, a metal layer is formed on the substrate; A first metal oxide layer is formed on a side of the metal layer away from the substrate, and the metal layer is oxidized to form a second metal oxide layer, so as to form a metal oxide film including the first metal oxide layer and the second metal oxide layer; the material of the first metal oxide layer is the same as that of the second metal oxide layer.
2. The method for preparing a transparent conductive oxide thin film according to claim 1, characterized in that: The step of forming a first metal oxide layer on a side of the metal layer away from the substrate and oxidizing the metal layer to form a second metal oxide layer is performed in a reaction chamber; the step of forming the first metal oxide layer on a side of the metal layer away from the substrate and oxidizing the metal layer to form a second metal oxide layer comprises: Oxidizing the metal layer to form a second metal oxide layer under a first power and a first gas environment, wherein the gas in the reaction chamber under the first gas environment includes oxygen; The first metal oxide layer is formed on the second metal oxide layer under a second power and a second gas environment; wherein the first power is greater than the second power.
3. The method for preparing a transparent conductive oxide thin film according to claim 2, characterized in that: The first power ranges from 800W to 1500W.
4. The method for preparing a transparent conductive oxide thin film according to claim 2, characterized in that: The gases in the reaction chamber under the first gas environment and the second gas environment both include oxygen and process gas, and the process gas includes at least one of inert gases; the proportion of oxygen in the reaction chamber under the first gas environment is a first ratio, and the proportion of oxygen in the reaction chamber under the second gas environment is a second ratio, and the first ratio is greater than the second ratio; Alternatively, the gas in the reaction chamber under the second gas environment does not include oxygen.
5. The method for preparing a transparent conductive oxide thin film according to claim 4, characterized in that: Under the first gas environment, the gas flow ratio of the process gas to oxygen in the reaction chamber ranges from 50:1 to 10:1; under the second gas environment, when the gas in the chamber includes oxygen, the gas flow ratio of the process gas to oxygen is greater than 95:
5.
6. The method for preparing a transparent conductive oxide thin film according to claim 1, characterized in that: The forming a first metal oxide layer on a side of the metal layer away from the substrate, and oxidizing the metal layer to form a second metal oxide layer comprises: forming the first metal oxide layer on a side of the metal layer away from the substrate to obtain a composite layer including the metal layer and the first metal oxide layer; The composite layer is heat-treated to diffuse oxygen ions in the first metal oxide layer into the metal layer, and the metal layer is transformed into a second metal oxide layer.
7. The method for preparing a transparent conductive oxide thin film according to claim 6, characterized in that: The heat treatment of the composite layer comprises: The composite layer is heat treated by an annealing process.
8. The method for preparing a transparent conductive oxide thin film according to claim 6, characterized in that: In a direction from the substrate to the metal layer, a thickness of the metal layer is less than one tenth of a thickness of the first metal oxide layer.
9. The method for preparing a transparent conductive oxide thin film according to any one of claims 1 to 8, characterized in that: The metal layer includes at least one of indium, tin, aluminum, zinc, gallium, strontium and titanium.
10. The method for preparing a transparent conductive oxide thin film according to any one of claims 1 to 8, characterized in that: In a direction from the substrate to the metal layer, the thickness of the metal layer is less than 10 nanometers.