A method for preparing a tco film

Abstract

The application discloses a TCO film preparation method, which comprises the following steps: sequentially performing H2, N2 and O2 three-step annealing on a substrate after depositing a TCO target material, and through the timing design of "reduction-buffering-passivation", the H2 atmosphere can effectively activate oxygen vacancies to improve the carrier mobility of the TCO film, the N2 atmosphere can improve the buffer environment to promote the grain growth in the annealing process, prevent the cross contamination between H2 and O2, improve the passivation effect of the O2 atmosphere, and thus improve the conductivity, light transmittance and structural stability of the TCO film.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of solar cells, in particular to a TCO film preparation method applied to the field of solar cells. BACKGROUND

[0002] TCO (transparent conductive oxide) film is an important part of thin-film solar cells, which has high light transmittance and low resistivity in the visible light wavelength range. High light transmittance in the visible light spectrum is beneficial to improve the conversion efficiency of photovoltaic cells and reduce energy loss. The performance of TCO film has an important influence on the efficiency and service life of thin-film solar cells, so the research and optimization of TCO film is one of the keys to improve the performance of thin-film solar cells.

[0003] Traditional TCO film preparation methods are difficult to simultaneously consider the conductivity, light transmittance and structural stability of the film, especially the performance is unstable at low temperature, which affects its application in thin-film transistors and other devices. The existing annealing method lacks precise control of the gas environment, often cannot effectively control the oxygen vacancy concentration and carrier concentration, resulting in poor film uniformity and high resistance, affecting the performance of the device.

[0004] Therefore, it has become the focus of current research to develop a method that can simultaneously improve the conductivity, light transmittance and structural stability of TCO film. Traditional annealing methods often fail to optimize these properties. How to precisely control the gas environment during the annealing process to comprehensively improve the performance of TCO film has become a technical problem to be solved. SUMMARY

[0005] In order to solve the problem that the traditional existing TCO film annealing process cannot effectively control the gas environment and improve the conductivity, light transmittance and structural stability of TCO film, the present application discloses a TCO film preparation method, which sequentially performs H2, N2 and O2 three-step annealing on the substrate after depositing the TCO target material. Through the timing design of "reduction-buffering-passivation", the H2 atmosphere can effectively activate the oxygen vacancies to improve the carrier mobility of the TCO film, the N2 atmosphere can improve the buffer environment to promote the grain growth during the annealing process, prevent cross contamination between H2 / O2, and improve the passivation effect of O2 atmosphere, thereby improving the conductivity, light transmittance and structural stability of the TCO film.

[0006] To achieve the above purpose, the specific solutions provided by the present application are as follows:

[0007] A TCO film preparation method, comprising the steps of: depositing a TCO target material on a substrate, and sequentially performing annealing in H2, N2 and O2 atmospheres to obtain a TCO film.

[0008] In one embodiment, the substrate comprises conductive glass, a battery structure.

[0009] In one embodiment, the battery structure comprises a single-junction battery structure or a stacked battery structure.

[0010] In one embodiment, the annealing temperature of each atmosphere is 150-300℃, and the annealing time is 5-30min.

[0011] In one embodiment, the gas flow rate of the H2 atmosphere is 100-500sccm.

[0012] In one embodiment, the gas flow rate of the N2 atmosphere is 100-500sccm.

[0013] In one embodiment, the gas flow rate of the O2 atmosphere is 100-500sccm.

[0014] In one embodiment, the TCO target material comprises one of ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), AZO (Aluminum-doped ZnO), GZO (Gallium-doped ZnO), SnO2, ZnO, In2O3, ICO (Cerium-doped Indium Oxide), IWO (Tungsten-doped Indium Oxide).

[0015] In one embodiment, the thickness of the TCO film is 5-200nm.

[0016] In one embodiment, the TCO target material is prepared by vacuum deposition, comprising the steps of: placing a substrate into a vacuum environment, setting the vacuum degree to 5.0×10 -4 -1.0×10 -4 Pa, adjusting the vacuum to 3.0×10 -1 Pa-8.0×10 -1 Pa, oxygen-argon percentage: 0.5%-10%, controlling the plating power to be 600-2000W, and depositing the TCO target material onto the substrate.

[0017] The application provides a TCO film preparation method, applied to the field of solar cells, by precisely controlling the gas atmosphere of the TCO film in the annealing process, using the gas atmosphere of H2, N2 and O2 to anneal the TCO film, effectively activating the oxygen vacancy concentration in the film by using H2 gas, improving the carrier mobility of the ITO film and improving the conductivity of the film; using N2 as a buffer treatment process to improve the stable heat treatment environment, promote grain growth and effectively maintain the structural stability of the film, while improving the light transmittance of the film; in the O2 annealing stage, by precisely controlling the atmosphere environment, the film stability and optical performance are synergistically improved through surface selective passivation. The application adopts a three-step gas atmosphere annealing regulation mechanism to comprehensively optimize the traditional annealing process, effectively improving the performance and structural stability of the film. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 The X-ray diffraction analyzer of the crystalline property analysis diagram of Example 1 and Comparative Examples 1-3 in the application.

[0019] In which No. 1 is the crystalline property analysis diagram of Comparative Example 1;

[0020] No. 2 is the crystalline property analysis diagram of Comparative Example 2;

[0021] No. 3 is the crystalline property analysis diagram of Comparative Example 3;

[0022] No. 4 is the crystalline property analysis diagram of Example 1. DETAILED DESCRIPTION

[0023] The technical solutions in the embodiments of the application will be described below in a clear and complete manner. Obviously, the described embodiments are only a part of the embodiments of the application, not all the embodiments.

[0024] In the description of the application, unless otherwise specified, the meaning of "a plurality of" is two or more; the orientations or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "left", "right", "inner", "outer", "front end", "rear end", "head", "tail", "vertical", "horizontal", "top", "bottom", "inner", "outer" are based on the orientations or positional relationships shown in the drawings, and are only for the purpose of facilitating the description of the application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, therefore cannot be understood as a limitation on the application. In addition, the terms "first", "second", "third" and the like are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0025] The application provides a TCO thin film preparation method, comprising the steps of: depositing a TCO target material on a substrate, and performing annealing in H2, N2 and O2 atmospheres in sequence to obtain a TCO thin film.

[0026] In one embodiment, the substrate comprises conductive glass, a battery structure. The preparation method can be applied on the conductive glass, and after the TCO thin film is prepared, functional layers such as a battery carrier layer and a light absorption layer are prepared in sequence to finally obtain a whole battery device; when applied to the battery structure, the method can be prepared on the buffer layer, carrier and other structure layers after the battery prepares the light absorption layer, which effectively improves the light absorption capacity and conductive performance of the device.

[0027] In one embodiment, the battery structure comprises a single-junction battery structure or a stacked battery structure. The battery structure described in the application comprises any structure which is not prepared with a top transparent electrode or metal battery, the single-junction battery structure can comprise a crystalline silicon battery and a perovskite battery structure, and the stacked battery structure can comprise a crystalline silicon perovskite stacked battery structure.

[0028] In one embodiment, the annealing temperature of each atmosphere is 150-300℃, and the annealing time is 5-30 min. The effects of annealing in different atmospheres are different, annealing in the H2 atmosphere can effectively reduce the oxygen vacancies in the thin film, improve the carrier mobility of the TCO thin film, and improve the conductivity of the thin film, then the N2 atmosphere is used for buffering transition, a stable heat treatment environment is provided, the growth of crystal grains is promoted, and the structural stability of the thin film is improved, at the same time, the H2 residue can be removed by using the N2 atmosphere, the H2 pollution during the passivation of the O2 atmosphere is reduced, and the passivation effect and the thin film quality are effectively improved.

[0029] In one embodiment, the gas flow in the H2 atmosphere is 100-500sccm. Preferably, the gas flow in the H2 atmosphere is 200sccm, the annealing temperature is 200℃, and the annealing time is 30 min.

[0030] In one embodiment, the gas flow in the N2 atmosphere is 100-500sccm. Preferably, the gas flow in the N2 atmosphere is 200sccm, the annealing temperature is 250℃, and the annealing time is 30 min.

[0031] In one embodiment, the gas flow in the O2 atmosphere is 100-500sccm. Preferably, the gas flow in the O2 atmosphere is 100sccm, the annealing temperature is 150℃, and the annealing time is 10 min.

[0032] In one embodiment, the TCO target material comprises one of ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), AZO (Aluminum-doped ZnO), GZO (Gallium-doped ZnO), SnO2, ZnO, In2O3, ICO (Cerium-doped Indium Oxide), IWO (Tungsten-doped Indium Oxide).

[0033] Preferably, the TCO target material is ITO (Indium Tin Oxide).

[0034] In one embodiment, the TCO thin film has a thickness of 5-200 nm.

[0035] In one embodiment, the TCO target material is prepared by vacuum deposition, comprising the steps of: placing a substrate into a vacuum environment, setting the vacuum degree to 5.0x10 -4 Pa, introducing argon and oxygen to adjust the vacuum to 3.0x10 -4 Pa, and controlling the film deposition power to be 600-2000 W, and depositing the TCO target material onto the substrate. -1 -1 Pa, and controlling the film deposition power to be 600-2000 W, and depositing the TCO target material onto the substrate.

[0036] In one embodiment, the TCO target material can also be deposited onto the surface of the substrate by magnetron sputtering, chemical vapor deposition, or solution method.

[0037] The following specific examples and comparative examples are provided to clearly and completely describe the technical solutions of the present application. Obviously, the described examples are part of the embodiments of the present application, rather than all the embodiments. Based on the examples in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0038] Example 1

[0039] The present embodiment provides a TCO thin film preparation method, comprising the steps of:

[0040] Step 1: Clean an electrically conductive glass.

[0041] Step 2: Place the electrically conductive glass into a PVD deposition device, set the ITO target material, and set the vacuum degree of the device to 3.0x10 -4 Pa, introduce argon and oxygen to adjust the vacuum to 5.0x10 -1 Pa, and control the film deposition power to be 1000 W, and form an ITO thin film on the electrically conductive glass, with a thickness of 100 nm.

[0042] ​Step 3: Put the conductive glass with ITO film into a vacuum annealing furnace, and anneal in H2 atmosphere, H2 flow rate is 200sccm, annealing temperature is 200℃, and annealing time is 30min.

[0043] Step 4: Take out the conductive glass after step 3, and put it into a vacuum annealing furnace, and anneal in N2 atmosphere, N2 flow rate is 200sccm, annealing temperature is 250℃, and annealing time is 30min.

[0044] Step 5: Take out the conductive glass after step 3, and put it into a vacuum annealing furnace, and anneal in O2 atmosphere, O2 flow rate is 100sccm, annealing temperature is 150℃, and annealing time is 10min.

[0045] Example 2

[0046] The embodiment provides a TCO film preparation method, and the difference from the embodiment 1 is that the flow rates of H2, N2 and O2 in steps 3-5 are all 120sccm.

[0047] Example 3

[0048] The embodiment provides a TCO film preparation method, and the difference from the embodiment 1 is that the flow rates of H2, N2 and O2 in steps 3-5 are all 350sccm.

[0049] Example 4

[0050] The embodiment provides a TCO film preparation method, and the difference from the embodiment 1 is that the annealing temperatures of H2, N2 and O2 in steps 3-5 are all 200℃.

[0051] Comparative Example 1

[0052] The comparative example provides a TCO film preparation method, which comprises the following steps:

[0053] Step 1: Clean a conductive glass.

[0054] Step 2: Put the conductive glass into a PVD deposition device, set an ITO target material, the vacuum degree of the device is 3.0x10 -4 Pa, introduce argon and oxygen to adjust the vacuum to 5.0x10 -1 Pa, the oxygen-argon percentage is 5%, the film deposition power is 1000W, and an ITO film with a thickness of 100nm is formed on the conductive glass.

[0055] Step 3: Put the conductive glass with ITO film into a vacuum annealing furnace, and anneal in H2 atmosphere, H2 flow rate is 200sccm, annealing temperature is 200℃, and annealing time is 30min.

[0056] Comparative Example 2

[0057] The present comparative example provides a TCO film preparation method, comprising the steps of:

[0058] Step 1: Clean a conductive glass.

[0059] Step 2: Put the conductive glass into a PVD deposition device, set an ITO target material, and adjust the vacuum degree of the device to 3.0x10 -4 Pa, and adjust the vacuum to 5.0x10 -1 Pa by introducing argon and oxygen, with an oxygen-argon percentage of 5%, a film plating power of 1000W, to form an ITO film on the conductive glass with a thickness of 100nm.

[0060] Step 3: Put the conductive glass with the ITO film into a vacuum annealing furnace, and perform annealing in an H2 atmosphere environment, with an H2 gas flow of 200sccm, an annealing temperature of 200℃, and an annealing time of 30min.

[0061] Step 4: Take out the conductive glass after Step 3, put it into a vacuum annealing furnace, and perform annealing in an O2 atmosphere environment, with an O2 gas flow of 100sccm, an annealing temperature of 150℃, and an annealing time of 10min.

[0062] Comparative Example 3

[0063] The present comparative example provides a TCO film preparation method, comprising the steps of:

[0064] Step 1: Clean a conductive glass.

[0065] Step 2: Put the conductive glass into a PVD deposition device, set an ITO target material, and adjust the vacuum degree of the device to 3.0x10 -4 Pa, and adjust the vacuum to 5.0x10 -1 Pa by introducing argon and oxygen, with an oxygen-argon percentage of 5%, a film plating power of 1000W, to form an ITO film on the conductive glass with a thickness of 100nm.

[0066] Step 3: Take out the conductive glass after Step 3, put it into a vacuum annealing furnace, and perform annealing in an O2 atmosphere environment, with an O2 gas flow of 100sccm, an annealing temperature of 150℃, and an annealing time of 10min.

[0067] Step 4: Take out the conductive glass after Step 3, put it into a vacuum annealing furnace, and perform annealing in an N2 atmosphere environment, with an N2 gas flow of 200sccm, an annealing temperature of 250℃, and an annealing time of 30min.

[0068] Step 5: The ITO thin film coated conductive glass was placed in a vacuum annealing furnace and annealed in an H2 atmosphere, with an H2 flow rate of 200 sccm, an annealing temperature of 200℃, and an annealing time of 30 min.

[0069] Electrical performance test: A four-probe tester and a Hall effect instrument were used for testing, and the equipment was calibrated and verified by using a standard sample. After the test data of the standard sample was qualified, the samples obtained in Examples 1-4 and Comparative Examples 1-3 were tested.

[0070] Optical performance test: A UV-vis instrument was used for testing, and the equipment was calibrated and verified by using a standard sample. After the test data of the standard sample was qualified, the samples obtained in Examples 1-4 and Comparative Examples 1-3 were tested.

[0071] The specific test results are shown in Table 1 below:

[0072] Table 1: Test results of the thin films obtained in Examples 1-4 and Comparative Examples 1-3

[0073] Group Film thickness nm Resistance Ω / sq Carrier concentration cm -3 ]] Mobility cm2 / (V-s) 550 nm position transmittance % Example 1 100 25.0 8.80E+20 61.885 88.545 Example 2 100 25.6 7.06E+20 59.139 88.120 Example 3 100 26.3 7.61E+20 58.225 88.326 Example 4 100 27.5 7.11E+20 56.425 88.225 Comparative Example 1 100 30.4 3.81E+20 35.094 84.150 Comparative Example 2 100 33.1 2.82E+20 26.254 86.900 Comparative Example 3 100 32.4 2.26E+20 24.034 86.336

[0074] The experimental data obtained show that the ITO thin film obtained by the technical scheme of the present application has excellent optical and electrical performance through three-step annealing in a gas environment. By annealing the prepared ITO thin film in H2, N2, and O2 gas atmosphere in sequence, the oxygen vacancies of the thin film are effectively activated, the carrier concentration and mobility are improved, the contact resistance is effectively reduced, and the performance and structural stability of the thin film are improved. The order of annealing cannot be reversed, and any order adjustment will destroy the balance of "bulk low resistance-interface stability". If O2 is passed first, a dense In2O3 layer will be formed on the surface, blocking the diffusion of H2 to the bulk phase, and the oxygen vacancies cannot be activated. If N2 is passed first, O2 / H2 cross contamination may occur. Figure 1 In the X-ray diffractometer analysis of Example 1 and Comparative Examples 1-3, the corresponding crystal face information (hkl) can be obtained, where hkl represents Miller indices, which are used to characterize the crystal face orientation of the material. In the corresponding figure, (211), (222), etc. are shown, and the intensity of the diffraction peak in the (222) direction is higher, indicating better crystallization. The ITO thin film obtained by the embodiments of the present application has good crystallization stability.

[0075] The above embodiments are only preferred embodiments of the present application. It should be noted that for ordinary skilled persons in the technical field, various changes, modifications, replacements, and deformations can be made to these embodiments without departing from the principles of the present application. These technical solutions obtained by equivalent replacement of the claims of the present application all fall within the protection scope of the present application, and the protection scope of the present application is defined by the appended claims and their equivalents.

Claims

1. A method for producing a TCO thin film, characterized by, The method comprises the steps of: depositing a TCO target material on a substrate, and annealing in H2, N2 and O2 atmospheres in sequence to obtain a TCO thin film. The annealing temperature of each atmosphere is 150-300 DEG C, and the annealing time is 5-30 min. The gas flow rate in the H2 atmosphere is 100-500 sccm. The gas flow rate in the N2 atmosphere is 100-500 sccm. The gas flow rate in the O2 atmosphere is 100-500 sccm.

2. The TCO thin film preparation method according to claim 1, characterized in that, The substrate comprises conductive glass or a battery structure.

3. The TCO thin film preparation method according to claim 2, characterized in that, The battery structure comprises a single-junction battery structure or a stacked battery structure.

4. The TCO thin film preparation method according to claim 1, wherein The TCO target material comprises one of ITO, IZO, AZO, GZO, SnO2, ZnO, In2O3, ICO and IWO.

5. The TCO thin film preparation method according to claim 1, wherein The thickness of the TCO thin film is 5-200 nm.

6. The TCO thin film preparation method according to claim 1, wherein The TCO target material is prepared by a vacuum deposition method, including the steps that: a substrate is placed into a vacuum environment, a vacuum degree is set to 5.0*10 -4 -1.0*10 -4 Pa, argon and oxygen are introduced to adjust the vacuum to 3.0*10 -1 Pa-8.0*10 -1 Pa, an oxygen-argon percentage is 0.5%-10%, a plating power is controlled to be 600-2000W, and the TCO target material is deposited on the substrate.

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