Nitrogen-doped ZnSnO film and preparation method thereof

Abstract

The invention relates to the technical field of ZnSnO thin film preparation, and particularly discloses a nitrogen-doped ZnSnO thin film and a preparation method thereof.The preparation method comprises the steps that by controlling parameters such as gas flow, annealing temperature and sputtering power, a nitrogen source is introduced into a ZnSnO system in a solid-phase mode, uniform doping of nitrogen is achieved, and the nitrogen-doped ZnSnO thin film is obtained; further, the nitrogen-doped ZnSnO thin film with high conductivity and stability is prepared; the method is simple in process, convenient to operate and suitable for large-scale production, and has important significance in improving the performance of the ZnSnO thin film and promoting the application of the ZnSnO thin film in the field of electronic devices.

Description

Technical Field

[0001] The present invention relates to the technical field of ZnSnO thin film preparation, and particularly to a nitrogen-doped ZnSnO thin film and a preparation method thereof. Background Art

[0002] With the continuous development of thin film technology, oxide thin films have been widely used in fields such as flat panel displays, solar cells, and sensors due to their unique physical and chemical properties. As a new type of oxide thin film material, ZnSnO thin films have received extensive attention from researchers due to their high mobility, good stability, and low cost. However, the conductivity of ZnSnO thin films still needs to be further improved to meet the requirements of high-performance electronic devices. Currently, researchers usually use doping modification methods to improve the performance of ZnSnO thin films. As a common doping element, the introduction of nitrogen can significantly change the energy band structure of the thin film and improve the conductivity of the thin film. Therefore, the preparation technology of nitrogen-doped ZnSnO thin films has become a current research hotspot. However, the existing preparation methods of nitrogen-doped ZnSnO thin films often have problems such as complex processes, high operation difficulty, and uneven doping, resulting in unstable performance of the prepared thin films and difficulty in meeting the requirements of practical applications.

[0003] Therefore, it is of great practical significance and application value to develop a simple, efficient, and evenly doped preparation method for nitrogen-doped ZnSnO thin films. Summary of the Invention

[0004] In view of the above deficiencies in the prior art, the purpose of the present invention is to provide a nitrogen-doped ZnSnO thin film and a preparation method thereof, aiming to solve the problems of complex processes, high operation difficulty, and uneven doping in the existing preparation methods of nitrogen-doped ZnSnO thin films, resulting in unstable performance and poor conductivity of the prepared thin films.

[0005] The technical solution of the present invention is as follows:

[0006] A preparation method of a nitrogen-doped ZnSnO thin film, which includes the steps of:

[0007] Mix ZnO, SnO, and Zn3N2 powders in a molar ratio of Zn:Sn:N of 7:3:(0.008 - 0.015), and sinter to form a composite target;

[0008] Place the composite target and a pretreated substrate parallel in the deposition chamber of a radio frequency magnetron sputtering device. First, open the chamber door of the deposition chamber to introduce nitrogen, then close the chamber door of the deposition chamber and perform a vacuum pumping treatment on the deposition chamber. Finally, open the chamber door of the deposition chamber again and introduce the working gas argon, and turn on the radio frequency source to continuously sputter for 5 - 15 minutes to form a deposited film on the surface of the pretreated substrate;

[0009] Put the deposited thin film into a tube resistance furnace, continuously introduce a mixed gas of oxygen and argon, and heat the tube resistance furnace to a preset temperature to anneal the deposited thin film, thereby obtaining the nitrogen-doped ZnSnO thin film.

[0010] The method for preparing the nitrogen-doped ZnSnO thin film, wherein, in the step of mixing ZnO, SnO, and Zn3N2 powders according to the molar ratio of Zn:Sn:N of 7:3:(0.008 - 0.015) and sintering to form a composite target, the sintering temperature is 800 - 1000 °C and the time is 4 - 6 h.

[0011] The method for preparing the nitrogen-doped ZnSnO thin film, wherein, in the step of continuously sputtering for 5 - 15 min by turning on the radio frequency source, the radio frequency power is 80 - 100 W.

[0012] The method for preparing the nitrogen-doped ZnSnO thin film, wherein, in the step of putting the deposited thin film into a tube resistance furnace, continuously introducing a mixed gas of oxygen and argon, and heating the tube resistance furnace to a preset temperature to anneal the deposited thin film, the volume ratio of oxygen to argon is 8:2 - 7:3.

[0013] The method for preparing the nitrogen-doped ZnSnO thin film, wherein, in the step of putting the deposited thin film into a tube resistance furnace, continuously introducing a mixed gas of oxygen and argon, and heating the tube resistance furnace to a preset temperature to anneal the deposited thin film, first heat it to 400 °C at a heating rate of 5 °C / min and keep it warm for 5 - 10 min, and then heat it to 535 - 635 °C at a heating rate of 15 °C / min and keep it warm for 10 - 15 min.

[0014] A nitrogen-doped ZnSnO thin film, which is prepared by using the method for preparing the nitrogen-doped ZnSnO thin film of the present invention.

[0015] Beneficial effects: By controlling parameters such as gas flow rate, annealing temperature, and sputtering power, the present invention introduces a nitrogen source into the ZnSnO system in a solid phase form to achieve uniform doping of nitrogen elements, and then prepares a nitrogen-doped ZnSnO thin film with high conductivity and stability; this method has a simple process and convenient operation, is suitable for large-scale production, and is of great significance for improving the performance of ZnSnO thin films and promoting their application in the field of electronic devices. Description of the Drawings

[0016] Figure 1 It is a flow chart of the method for preparing a nitrogen-doped ZnSnO thin film of the present invention.

[0017] Figure 2 It is an electron microscope image of the deposited thin film without annealing treatment in Example 1 at a molecular scale of 400 nm.

[0018] Figure 3 TEM image of the nitrogen-doped ZnSnO thin film prepared in Example 1 at a molecular scale of 500 nm.

[0019] Figure 4 TEM image of the nitrogen-doped ZnSnO thin film prepared in Example 2 at a molecular scale of 500 nm.

[0020] Figure 5 TEM image of the nitrogen-doped ZnSnO thin film prepared in Example 3 at a molecular scale of 500 nm. Detailed implementation manners

[0021] The present invention provides a nitrogen-doped ZnSnO thin film and a preparation method thereof. To make the objectives, technical solutions and effects of the present invention clearer and more definite, the present invention is further described in detail below. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] Please refer to Figure 1 , Figure 1 which is a flowchart of a preparation method of a nitrogen-doped ZnSnO thin film provided by the present invention. As shown in the figure, it includes the steps:

[0023] S10. Mix ZnO, SnO, and Zn3N2 powders according to the molar ratio of Zn:Sn:N of 7:3:(0.008 - 0.015), and sinter to form a composite target.

[0024] S20. Place the composite target and the pretreated substrate parallel in the deposition chamber of a radio frequency magnetron sputtering device. First, open the chamber door of the deposition chamber to introduce nitrogen, then close the chamber door of the deposition chamber and perform a vacuum pumping treatment on the deposition chamber. Finally, open the chamber door of the deposition chamber again and introduce the working gas argon, and turn on the radio frequency source to continuously sputter for 5 - 15 minutes to form a deposited film on the surface of the pretreated substrate.

[0025] S30. Place the deposited film in a tube resistance furnace, continuously introduce a mixed gas of oxygen and argon, and heat the tube resistance furnace to a preset temperature to perform an annealing treatment on the deposited film to obtain the nitrogen-doped ZnSnO thin film.

[0026] Specifically, in this embodiment, a silicon oxide wafer with a diameter of 100 ± 0.3 mm and a thickness of 450 ± 10 μm is first cut as the substrate; the substrate is ultrasonically cleaned in acetone solution for 5 - 10 min, then the used acetone solution is replaced and the cleaning is repeated twice. As an organic solvent, acetone can effectively dissolve oils and organic pollutants; then, the substrate is ultrasonically cleaned in deionized water for 5 - 10 min. After cleaning, the used deionized water is replaced and the cleaning is repeated twice. The ion impurities are removed by ultrasonic cleaning with deionized water to avoid the introduction of impurities into the film during the sputtering process; finally, the moisture on the surface of the substrate is blown dry with high-purity nitrogen to obtain a pretreated substrate. Blowing dry with nitrogen can prevent water molecules from adsorbing on the surface of the substrate and prevent the formation of an oxide layer or defects during sputtering.

[0027] Then, in this embodiment, ZnO, SnO, and Zn3N2 powders are mixed in a ratio of Zn:Sn:N molar ratio of 7:3:(0.008 - 0.015) and sintered to form a composite target. Through a large number of preliminary experiments in this embodiment, the performance of ZnSnO films with different nitrogen contents was tested. The results showed that when the nitrogen content was less than 0.008, the improvement effect of nitrogen doping on the electrical conductivity of the film was not obvious and the increase in carrier concentration was limited; when the nitrogen content was higher than 0.015, too many nitrogen atoms would cause serious lattice distortion and generate a large number of defects, which would instead reduce the electrical properties and stability of the film. After repeated experimental verification, it was found that mixing and sintering in the range of Zn:Sn:N molar ratio of 7:3:(0.008 - 0.015) could effectively improve the electrical conductivity of the nitrogen-doped ZnSnO film. This shows that appropriate nitrogen doping can change the energy band structure of the film, introduce additional carriers, and improve the electrical conductivity; when the nitrogen content is in this ratio range, nitrogen atoms can be more evenly distributed in the ZnSnO lattice to form effective doping and enhance the electron transport ability. The research also shows that compared with other ratios, this ratio helps to ensure the stability of the film. The appropriate nitrogen doping amount avoids the problems of excessive or too small lattice distortion caused by too much or too little nitrogen, enables the film to have a good crystalline structure, and can maintain stable electrical properties under different environmental conditions.

[0028] In this embodiment, the sintering temperature is controlled at 800 - 1000 °C and the time is 4 - 6 h. When determining the sintering temperature, it is necessary to avoid excessive decomposition of Zn3N2 caused by too high a temperature, and at the same time ensure that the temperature is high enough to allow appropriate diffusion and reaction between the components. In this embodiment, experiments such as thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) are carried out to monitor the mass change and heat change of the target powder during heating. Through these analyses, it is found that in the temperature range of 800 - 1000 °C, obvious signs of mutual diffusion and reaction among the components of the target start to appear, and Zn3N2 begins to decompose. For the sintering time, within this temperature range, different initial times can be set for experiments, such as 2 hours, 4 hours, and 6 hours. The experimental results show that when the sintering time is 4 - 6 hours, the density and composition uniformity of the target are better, which can not only ensure sufficient reaction and diffusion of each component, but also prevent excessive decomposition of Zn3N2 or excessive grain growth due to too long a time.

[0029] The finally prepared nitrogen-doped ZnSnO thin film has certain requirements for the quality of the target. If it is desired that the thin film has high conductivity and good stability, the target needs to have good composition uniformity and high density. Through thin film sputtering experiments on targets prepared at different sintering temperatures and times in the early stage, and analyzing the performance of the thin films, it is found that: when using the target sintered at 800 - 1000 °C for 4 - 6 hours to prepare the thin film, the conductivity of the thin film is relatively high, the carrier concentration distribution is uniform, and the stability is good. However, for the thin films prepared using targets with too low sintering temperature or too short time, there are problems of uneven nitrogen doping and low conductivity; for the thin films prepared using targets with too high sintering temperature or too long time, due to excessive decomposition of Zn3N2 in the target, insufficient nitrogen doping may occur, which also affects the performance of the thin film. Therefore, based on the comprehensive test results of the thin film performance, the suitable sintering temperature for the target to prepare high-performance nitrogen-doped ZnSnO thin films is determined to be 800 - 1000 °C and the time is 4 - 6 h.

[0030] Next, in this embodiment, the composite target and the pretreated substrate are placed parallel to each other in the deposition chamber of a radio frequency magnetron sputtering device. First, the deposition chamber door is opened to introduce nitrogen gas, then the deposition chamber door is closed and the deposition chamber is evacuated. Finally, the deposition chamber door is opened again and the working gas argon is introduced. The radio frequency source is turned on and sputtering is continued for 5 - 15 minutes with a radio frequency power of 80 - 100 W to form a deposited film on the surface of the pretreated substrate. During this process, argon ions obtain energy under the action of the radio frequency electric field and strike the surface of the composite target at high speed. Since the target contains Zn3N2, under the bombardment of argon ions, the atoms on the target surface, including nitrogen atoms, are sputtered out. These sputtered atoms are transported in the gas environment in the deposition chamber and finally deposited on the substrate surface. Through this physical sputtering process, nitrogen elements are transferred from the ceramic target to the ZnSnO system in a solid phase form, avoiding the uniformity defects of liquid phase doping, thereby realizing the preliminary introduction of nitrogen elements into the film. During the sputtering process, in addition to the introduction of nitrogen elements by physical sputtering, a series of chemical reactions also occur. The nitrogen atoms deposited on the substrate surface will interact with the zinc and tin atoms in ZnO and SnO. The outer electron structure of nitrogen atoms enables them to form chemical bonds with zinc and tin atoms, and some nitrogen atoms replace the oxygen atom positions in the lattice to form a nitrogen-doped structure. This doped structure changes the energy band structure of the ZnSnO film. The introduction of nitrogen atoms generates additional electrons, increasing the carrier concentration, thereby improving the electrical conductivity of the film.

[0031] Finally, in this embodiment, the deposited film is placed in a tube resistance furnace, and a mixed gas of oxygen and argon is continuously introduced while the tube resistance furnace is heated to a preset temperature to anneal the deposited film, thereby obtaining the nitrogen-doped ZnSnO film. In this embodiment, the volume ratio of oxygen to argon is 8:2 - 7:3. During the annealing process, first, the temperature is raised at a rate of 5 °C / min to 400 °C and held for 5 - 10 minutes, and then the temperature is raised at a rate of 15 °C / min to 535 - 635 °C and held for 10 - 15 minutes.

[0032] Specifically, since the traditional annealing process is carried out in a pure oxygen atmosphere, in this case, nitrogen elements may be lost to a certain extent due to factors such as high temperature, affecting the doping effect and performance of the thin film. In the annealing atmosphere design of this embodiment, an appropriate amount of inert gas argon is added to form a mixed atmosphere. The presence of argon can play a "buffering" role, reducing the oxygen partial pressure around nitrogen elements. Different ratios of oxygen and argon mixed atmospheres can provide a more favorable environment for the repair of thin film defects. Oxygen can participate in the repair reaction of some defects during the annealing process, while the stable characteristics of argon help to maintain the stability of the internal microenvironment of the thin film. When the ratio of oxygen to argon is 8:2 - 7:3, while oxygen repairs defects, argon can reduce the possible new defects generated during the repair process, promote the improvement of the internal lattice structure of the thin film, and improve the crystallization quality of the thin film. Under this mixed atmosphere, defects such as oxygen vacancies inside the thin film are better repaired, which helps to improve the electrical properties and stability of the thin film.

[0033] Furthermore, in the traditional uniform heating rate annealing method, large thermal stresses will be generated during the heating process of the thin film. Due to the difference in the thermal expansion coefficients of the thin film and the substrate material, rapid heating will cause a sharp increase in thermal stress, which may cause cracks or other structural defects in the thin film, affecting the performance of the thin film. For the segmented heating rate annealing curve, in the initial stage, the temperature is raised to 400 °C at a slower heating rate of 5 °C / min and held for 5 - 10 min. During this process, the thin film and the substrate can gradually adapt to the temperature change, slowly release part of the thermal stress, reduce the risk of structural damage caused by excessive thermal stress, and lay a good foundation for the subsequent heating and annealing; in the second half of the segmented heating rate annealing curve, the temperature is raised to the final annealing temperature of 535 - 635 °C at a faster heating rate of 15 °C / min and held for 10 - 15 min. On the basis of the preliminary release of the thermal stress in the early stage, rapid heating can accelerate the diffusion rate of atoms, promote the rearrangement of atoms inside the thin film and the crystallization process. During the process of raising the temperature to 535 - 635 °C and holding for 10 - 15 min, the crystal structure of the thin film is more complete, the grain growth is more uniform, and the grain boundary defects are reduced. This optimized temperature curve can effectively improve the microstructure of the thin film, improve the crystallization quality of the thin film, and further improve the electrical conductivity and stability of the thin film, making the nitrogen-doped ZnSnO thin film perform better in the application of electronic devices.

[0034] The present invention introduces a nitrogen source into the ZnSnO system in a solid phase form by controlling parameters such as gas flow rate, annealing temperature, and sputtering power, realizes the uniform doping of nitrogen elements, and further prepares a nitrogen-doped ZnSnO thin film with high conductivity and stability.

[0035] The following further explains the present invention through specific embodiments:

[0036] Example 1

[0037] A preparation method of nitrogen-doped ZnSnO thin film, comprising the following steps:

[0038] Pretreatment of substrate: Cut a silicon oxide wafer with a diameter of 100 ± 0.3 mm and a thickness of 450 ± 10 μm as the substrate; place the substrate in acetone solution and ultrasonically clean it for 8 min, then replace the used acetone solution and repeat the cleaning twice. Acetone, as an organic solvent, can effectively dissolve grease and organic pollutants; then, place the substrate in deionized water and ultrasonically clean it for 8 min. After cleaning, replace the used deionized water and repeat the cleaning twice. Ultrasonic cleaning with deionized water can remove ionic impurities and avoid the introduction of impurities into the thin film during the sputtering process; finally, dry the moisture on the surface of the substrate with high-purity nitrogen. Nitrogen drying can prevent water molecules from adsorbing on the surface of the substrate and prevent the formation of an oxide layer or defects during sputtering.

[0039] Preparation of ZnSnO:N thin film: Mix ZnO, SnO, and Zn3N2 powders according to the molar ratio of Zn:Sn:N of 7:3:0.01, and then sinter at 900 °C for 5 h to form a composite target; then place the composite target and the pretreated substrate parallel in the deposition chamber of a radio frequency magnetron sputtering device. First, open the chamber door of the deposition chamber and introduce nitrogen, then close the chamber door of the deposition chamber and perform a vacuum pumping process on the deposition chamber. Finally, open the chamber door of the deposition chamber again and introduce the working gas argon, and turn on the radio frequency source to continuously sputter for 10 min. The radio frequency power is 90 W to form a deposited thin film on the surface of the pretreated substrate; finally, place the deposited thin film in a tube resistance furnace, continuously introduce a mixed gas of oxygen and argon, and heat the tube resistance furnace to a preset temperature to perform annealing treatment on the deposited thin film. The volume ratio of oxygen to argon is 8:2, and during the annealing process, first heat at a heating rate of 5 °C / min to 400 °C and hold for 8 min, then heat at a heating rate of 15 °C / min to 535 °C and hold for 12 min to obtain the nitrogen-doped ZnSnO thin film.

[0040] Example 2

[0041] A preparation method of nitrogen-doped ZnSnO thin film, comprising the following steps:

[0042] Pretreatment of the substrate: Cut a silicon oxide wafer with a diameter of 100 ± 0.3 mm and a thickness of 450 ± 10 μm as the substrate; place the substrate in an acetone solution and ultrasonically clean it for 5 min, then replace the used acetone solution and repeat the cleaning twice. Acetone, as an organic solvent, can effectively dissolve grease and organic pollutants; then, place the substrate in deionized water and ultrasonically clean it for 5 min. After cleaning, replace the used deionized water and repeat the cleaning twice. Ultrasonic cleaning with deionized water can remove ionic impurities and avoid the introduction of impurities into the thin film during the sputtering process; finally, blow dry the moisture on the surface of the substrate with high-purity nitrogen to obtain a pretreated substrate. Nitrogen drying can prevent water molecules from adsorbing on the surface of the substrate and prevent the formation of an oxide layer or defects during sputtering.

[0043] Preparation of the ZnSnO:N thin film: Mix ZnO, SnO, and Zn3N2 powders in a molar ratio of Zn:Sn:N of 7:3:0.008, and then sinter at 800 °C for 6 h to form a composite target; then place the composite target and the pretreated substrate parallel in the deposition chamber of a radio frequency magnetron sputtering device. First, open the chamber door of the deposition chamber to introduce nitrogen, then close the chamber door of the deposition chamber and evacuate the deposition chamber, and finally open the chamber door of the deposition chamber again and introduce the working gas argon. Turn on the radio frequency source and continuously sputter for 5 min with a radio frequency power of 100 W to form a deposited thin film on the surface of the pretreated substrate; finally, place the deposited thin film in a tube resistance furnace, continuously introduce a mixed gas of oxygen and argon, and heat the tube resistance furnace to a preset temperature to anneal the deposited thin film. The volume ratio of oxygen to argon is 8:2, and during the annealing process, first heat at a heating rate of 5 °C / min to 400 °C and hold for 5 min, and then heat at a heating rate of 15 °C / min to 585 °C and hold for 10 min to obtain the nitrogen-doped ZnSnO thin film.

[0044] Example 3

[0045] A method for preparing a nitrogen-doped ZnSnO thin film, which comprises the following steps:

[0046] Pretreatment of the substrate: Cut a silicon oxide wafer with a diameter of 100 ± 0.3 mm and a thickness of 450 ± 10 μm as the substrate; place the substrate in an acetone solution and ultrasonically clean it for 10 min, then replace the used acetone solution and repeat the cleaning twice. Acetone, as an organic solvent, can effectively dissolve grease and organic pollutants; then, place the substrate in deionized water and ultrasonically clean it for 10 min. After cleaning, replace the used deionized water and repeat the cleaning twice. Ultrasonic cleaning with deionized water can remove ionic impurities and avoid the introduction of impurities into the thin film during the sputtering process; finally, blow dry the moisture on the surface of the substrate with high-purity nitrogen to obtain a pretreated substrate. Nitrogen drying can prevent water molecules from adsorbing on the surface of the substrate and prevent the formation of an oxide layer or defects during sputtering.

[0047] Preparation of ZnSnO:N thin film: ZnO, SnO, and Zn3N2 powders were mixed in a ratio of 7:3:0.015 in terms of the molar ratio of Zn:Sn:N, and then sintered at 1000 °C for 4 h to form a composite target. Then, the composite target and the pretreated substrate were placed parallel in the deposition chamber of a radio frequency magnetron sputtering device. First, the deposition chamber door was opened to introduce nitrogen, then the deposition chamber door was closed and the deposition chamber was evacuated. Finally, the deposition chamber door was opened again and the working gas argon was introduced, and the radio frequency source was turned on to continuously sputter for 15 min with a radio frequency power of 80 W to form a deposited thin film on the surface of the pretreated substrate. Finally, the deposited thin film was placed in a tube resistance furnace, and a mixed gas of oxygen and argon was continuously introduced and the tube resistance furnace was heated to a preset temperature to anneal the deposited thin film. The volume ratio of oxygen to argon was 7:3, and during the annealing process, it was first heated to 400 °C at a heating rate of 5 °C / min and held for 10 min, and then heated to 635 °C at a heating rate of 15 °C / min and held for 10 min to obtain the nitrogen-doped ZnSnO thin film.

[0048] The nitrogen-doped ZnSnO thin films prepared in Examples 1-3 and the deposited thin film without annealing treatment in Example 1 were observed by electron microscopy, and the results are as Figures 2 - 5 shown. Figure 2 Figure (a) is an electron micrograph of the deposited thin film without annealing treatment in Example 1 at a molecular scale of 400 nm. Figures 3 - 5 Figures (b), (c), and (d) are electron micrographs of the nitrogen-doped ZnSnO thin films prepared in Examples 1-3 at a molecular scale of 500 nm, respectively. It can be seen from Figure 2 the electron micrographs that the surface of the thin film is relatively rough, with some irregular protrusions or defects, indicating that the growth of the nitrogen-doped ZnSnO thin film is not sufficiently ordered and there may be many defects in the crystal structure and the atomic arrangement is not regular enough without annealing treatment. This may be because during the sputtering deposition process, the migration and arrangement of atoms do not have enough energy and time to be optimized, resulting in an unsatisfactory microstructure of the thin film. Compared with Figure 2 that, Figures 3 - 5 the surfaces of the thin films annealed at 535 °C, 585 °C, and 635 °C in (b), (c), and (d) are smoother and more uniform, and the particle sizes are relatively more consistent, indicating that the annealing treatment has a positive effect on the microstructure of the thin film. During the annealing process, atoms obtain enough energy to migrate and rearrange, which helps to reduce defects, promote the perfection of the crystal structure and the growth of grains, make the microstructure of the thin film more ordered, and thus improve the quality and performance of the thin film.

[0049] The resistivity of the nitrogen-doped ZnSnO thin films prepared in Examples 1-3 was measured by the four-probe method, and the carrier concentration and mobility of the thin films were measured by a Hall effect tester. The results are shown in Table 1:

[0050] Table 1 Test Results

[0051]

[0052] It can be seen from the data in Table 1 that nitrogen doping significantly improves the conductivity of the ZnSnO film, and the increase in the annealing temperature is beneficial to the effective activation of nitrogen elements.

[0053] It should be understood that the application of the present invention is not limited to the above examples. For those of ordinary skill in the art, improvements or transformations can be made according to the above description, and all such improvements and transformations should fall within the protection scope of the appended claims of the present invention.

Claims

1. A method for preparing a nitrogen-doped ZnSnO thin film, characterized in that: Includes steps: Mix ZnO, SnO and Zn3N2 powders in a molar ratio of Zn:Sn:N of 7:3:(0.008-0.015), and sinter to form a composite target; The composite target material and the pre-treated substrate are placed in parallel in a deposition chamber of a radio frequency magnetron sputtering device, the deposition chamber door is opened to introduce nitrogen, the deposition chamber door is closed and the deposition chamber is evacuated, and finally the deposition chamber door is opened and argon gas is introduced as a working gas, and the radio frequency source is turned on for continuous sputtering for 5-15 minutes to form a deposited film on the surface of the pre-treated substrate; The deposited film is placed in a tubular resistance furnace, a mixed gas of oxygen and argon is continuously introduced, and the temperature of the tubular resistance furnace is raised to a preset temperature to perform annealing treatment on the deposited film, thereby obtaining the nitrogen-doped ZnSnO film.

2. The method for preparing the nitrogen-doped ZnSnO thin film according to claim 1, characterized in that: The ZnO, SnO and Zn3N2 powders are mixed in a molar ratio of Zn:Sn:N of 7:3:(0.008-0.015), and in the step of sintering to form a composite target material, the sintering temperature is 800-1000°C and the time is 4-6h.

3. The method for preparing the nitrogen-doped ZnSnO thin film according to claim 1, characterized in that: In the step of turning on the RF source and continuing sputtering for 5-15 minutes, the RF power is 80-100W.

4. The method for preparing the nitrogen-doped ZnSnO thin film according to claim 1, characterized in that: In the step of placing the deposited film in a tubular resistance furnace, continuously introducing a mixed gas of oxygen and argon and heating the tubular resistance furnace to a preset temperature to anneal the deposited film, the volume ratio of oxygen to argon is 8:2-7:

3.

5. The method for preparing the nitrogen-doped ZnSnO thin film according to claim 1, characterized in that: The deposited film is placed in a tubular resistance furnace, a mixed gas of oxygen and argon is continuously introduced, and the tubular resistance furnace is heated to a preset temperature to anneal the deposited film. The temperature is first increased to 400°C at a heating rate of 5°C / min and kept at this temperature for 5-10 minutes, and then increased to 535-635°C at a heating rate of 15°C / min and kept at this temperature for 10-15 minutes.

6. A nitrogen-doped ZnSnO thin film, characterized in that: The film is prepared by the method for preparing the nitrogen-doped ZnSnO film according to any one of claims 1 to 5.

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