Mist chemical vapor deposition method for preparing high-quality tin dioxide thin film and tantalum doping of tin dioxide thin film

Abstract

The invention provides a fog chemical vapor deposition method for preparing a high-quality stannic oxide film and tantalum doping thereof, which comprises the following steps: taking sapphire as a substrate, taking stannous acetate as a tin source, taking ethanol / ethylene glycol and deionized water as solvents, and adding a proper amount of hydrochloric acid to promote the stannous acetate to dissolve; placing the prepared solution as a precursor into an atomizer container, placing a substrate at a certain position in a tubular furnace, heating the tubular furnace and preserving heat, atomizing the precursor solution in the heat preservation process, and transmitting the atomized precursor solution to the substrate through carrier gas to obtain the high-quality stannic oxide single crystal film. Tantalum pentachloride is used as a doped tantalum source, ethyl alcohol / ethylene glycol and deionized water are used as solvents, the precursor is placed into an atomizer, ethyl alcohol / ethylene glycol is added, the source material is atomized in the heat preservation process, and the tantalum-doped tin dioxide single crystal film is obtained on a substrate through carrier gas transmission. The method is simple in operation steps and easy to implement. And the used source materials are easy to obtain, so that the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of semiconductor materials, specifically to a fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and their tantalum doping. Background Technology

[0002] Tin dioxide (SnO2), as a third-generation semiconductor material, has a direct bandgap of 3.6 eV, which is wider and has higher visible light transmittance than traditional wide-bandgap semiconductor materials such as silicon carbide, zinc oxide, and gallium nitride. In addition, SnO2 possesses chemical stability, high temperature resistance, strong acid and alkali resistance at room temperature, high saturated electron mobility, and abundant reserves, making it widely used in gas sensors, optoelectronic devices, and solar cells. However, current literature reports that epitaxially grown SnO2 crystals have relatively poor quality, making it difficult to meet the requirements for semiconductor device fabrication.

[0003] Currently, the preparation of tantalum-doped tin dioxide thin films using various methods suffers from drawbacks such as requiring precise equipment, high preparation costs, complex process parameters, poor crystallinity, and high resistivity. These problems indicate that existing technologies face challenges in terms of the preparation quality and methods of SnO2 and tantalum-doped SnO2 single crystal thin films. Simpler equipment and methods are needed to fabricate high-crystallinity SnO2 single crystal thin films and low-resistivity tantalum-doped SnO2, thereby improving the performance of SnO2-based semiconductor devices. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the present invention aims to provide a fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and tantalum-doped tin dioxide films, thereby solving the problems mentioned in the background section. The present invention features simple operation steps, avoids complex processes, and is therefore easy to implement. The raw materials used are stannous oxyacetate, tantalum pentachloride, hydrochloric acid, ethanol, and ethylene glycol, all of which are common, readily available, and inexpensive, reducing the production cost of tin dioxide thin films and tantalum-doped tin dioxide thin films, and promoting the application of tin dioxide in the field of wide-bandgap semiconductor materials.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: a fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and their tantalum doping, comprising the following steps:

[0006] S1.1. Use sapphire to grow tin dioxide single crystal epitaxial thin films. After ultrasonic cleaning of the substrate, a clean pretreated substrate is obtained. Then, the substrate is attached to the sample stage with high-temperature inorganic adhesive and the sample stage is placed in a tube furnace.

[0007] S1.2. Stannous acetate and tantalum pentachloride are used as precursors. After weighing, they are placed in a beaker and hydrochloric acid and ethanol / ethylene glycol are added to dissolve stannous acetate and tantalum pentachloride. Deionized water is added to prepare a certain concentration to obtain a colorless and transparent precursor solution. The solution is placed in the nebulizer container and waited for sonication.

[0008] S1.3 After the heating is completed, keep it at the temperature for a period of time, then turn on the atomizer so that the precursor solution is atomized into very small droplets.

[0009] S1.4. Two gas streams are introduced: one stream is a carrier gas that guides the atomized precursor solution into the tube furnace, and the other stream is oxygen that is directly introduced into the tube furnace, so that the precursor solution and oxygen react to form a tin oxide film.

[0010] Furthermore, the purity of stannous acetate and tantalum pentachloride in step S1.2 is not less than 95%, and the atomic ratio of tin to tantalum in the precursor is 100:1.

[0011] Furthermore, in step S1.3, the atomization power of the atomizer is 1%-100% of the total atomization power.

[0012] Furthermore, in step S1.4, the tubular furnace is heated to the growth and deposition temperature and maintained for 2 hours, wherein the growth and deposition temperature is 600℃-700℃.

[0013] Furthermore, it also includes a method for preparing high-quality tin dioxide single-crystal thin films, the steps of which are as follows:

[0014] S2.1. Using sapphire as the heteroepitaxial substrate for growing tin dioxide single crystal thin films, the substrate is ultrasonically cleaned with ethanol and deionized water in sequence, and the substrate surface is dried with high-purity nitrogen to obtain a clean pretreated substrate. The substrate is then attached to the sample stage with high-temperature inorganic adhesive and the sample stage is placed in a tube furnace.

[0015] S2.2 Using stannous acetate as the tin source, weigh it and put it into a beaker. Add ethanol and hydrochloric acid in sequence to fully dissolve the stannous acetate. Add deionized water to prepare a certain concentration to obtain a colorless and transparent precursor solution. Put it into the nebulizer container and wait for sonication.

[0016] S2.3 After the heating is completed, keep it at the temperature for a period of time, then turn on the atomizer so that the precursor solution is atomized into very small droplets.

[0017] S2.4. Two gas streams are introduced. One stream is a carrier gas that introduces the precursor solution, which has been atomized into small droplets, into the tube furnace. The other stream is oxygen, which is directly introduced into the tube furnace to provide part of the oxygen source for thin film deposition and to begin the growth of tin oxide thin film.

[0018] S2.5 After the reaction is complete, the tin oxide film growth is finished. First, stop ultrasonic atomization, then turn off the oxygen and stop heating after 3 minutes. Allow the substrate to cool to room temperature naturally, and the experimental procedure is complete.

[0019] Furthermore, in step S2.1, the sapphire substrate is a single-crystal preferred-oriented substrate.

[0020] Furthermore, in step S2.2, the purity of stannous acetate is not less than 95%, and the precursor concentration is 0.01~0.04 mol / L.

[0021] Furthermore, in step S2.3, the atomization power is 10%-100% of the total atomization power.

[0022] Furthermore, in step S2.4, the tubular furnace is heated to the growth deposition temperature and then the film is grown at a constant temperature, wherein the growth deposition temperature is 650℃-850℃.

[0023] The beneficial effects of this invention are:

[0024] 1. This method uses a simple preparation apparatus and has simple operating steps, without involving complex operations, making it easy to implement. The raw materials used are stannous acetate, tantalum pentachloride, hydrochloric acid, ethanol, and ethylene glycol, all of which are relatively common, readily available, and inexpensive.

[0025] 2. The method for preparing high-quality tin dioxide thin films and its tantalum-doped fog chemical vapor deposition can more easily prepare conductive tin dioxide thin films with good crystal quality, and can mass-produce high-quality tantalum-doped tin dioxide single crystal thin films, reduce the production cost of tantalum-doped tin dioxide thin films, and promote the application of tin dioxide in the field of wide bandgap semiconductor materials. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the fog chemical vapor deposition system used in the embodiments of the present invention;

[0027] Figure 2 This is a schematic diagram illustrating the experimental principle of tin dioxide growth on a substrate in an embodiment of the present invention.

[0028] Figure 3 The XRD full spectrum of tin dioxide thin films grown at different temperatures without the use of ethanol and ethylene glycol in Examples 1 and 2 of this invention;

[0029] Figure 4 These are the thin film XRD rocking curves of Examples 1 and 2 of the present invention without the use of ethanol and ethylene glycol;

[0030] Figure 5 The XRD full spectrum of thin film samples prepared using ethanol of different concentrations in Example 1 of this invention;

[0031] Figure 6 The XRD rocking curves of thin film samples prepared using ethanol of different concentrations in Example 1 of this invention are shown.

[0032] Figure 7 The XRD rocking curves of tin dioxide thin film samples prepared at different temperatures in Example 1 of this invention;

[0033] Figure 8 The images show the XRD rocking curves of different tantalum doping concentrations prepared in Example 1 of this invention.

[0034] Figure 9 This is a SEM image of the thin film sample prepared using ethanol in Example 1 of the present invention.

[0035] Figure 10 The XRD rocking curves of thin film samples prepared using different concentrations of ethylene glycol in Example 2 of this invention are shown.

[0036] Figure 11 This is a SEM image of the thin film prepared using ethylene glycol in Example 2 of the present invention.

[0037] Figure 12 The full XRD spectra of thin films without ethanol in Examples 3, 4, and 5 of this invention;

[0038] Figure 13 These are the thin film XRD rocking curves of Examples 3, 4, and 5 of the present invention without the use of ethanol;

[0039] Figure 14 The XRD full spectrum of the thin film samples prepared at different ethanol contents in Example 3 of this invention;

[0040] Figure 15 The XRD rocking curves of the thin film samples prepared at different ethanol contents in Example 3 of this invention are shown.

[0041] Figure 16 The XRD full spectrum of tin dioxide thin film samples prepared at different substrate distances using 7.5 ml of ethanol in Example 4 of this invention;

[0042] Figure 17 The image shows the XRD rocking curves of tin dioxide thin film samples prepared at different substrate distances using 7.5 ml of ethanol in Example 4 of this invention.

[0043] Figure 18 The XRD full spectrum of tin dioxide thin film samples prepared at different temperatures with 7.5 ml ethanol and 7 cm substrate distance in Example 5 of this invention;

[0044] Figure 19The XRD rocking curves of tin dioxide thin film samples prepared at different temperatures with 7.5 ml ethanol and 7 cm substrate distance in Example 5 of this invention are shown.

[0045] Figure 20 This is a SEM image of the surface morphology of the thin film sample prepared in Example 5 of the present invention;

[0046] Figure 21 This is a SEM cross-sectional morphology image of the sample prepared in Example 5 of the present invention. Detailed Implementation

[0047] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0048] Please see Figures 1 to 21 The present invention provides the following technical solution: a fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and their tantalum doping:

[0049] Example 1:

[0050] This embodiment uses ethanol to assist in the preparation of Ta-doped tin oxide thin films. The specific steps are as follows:

[0051] (1) Using a mixture of stannous acetate and tantalum pentachloride powder as the source material, weigh 0.4985 g of stannous acetate and 0.0072 g of tantalum pentachloride (Sn to Ta atomic ratio of 100:1) using an electronic balance, mix them in a beaker, add 10 ml of deionized water to dissolve them into a liquid state, then add 2 ml of concentrated hydrochloric acid and 1-5 ml of ethanol and stir until completely free of precipitate. Simultaneously, attach the cleaned R-face sapphire to the sample stage using high-temperature inorganic adhesive. A schematic diagram of the fog chemical vapor deposition system is shown below. Figure 1 As shown.

[0052] (2) Set the temperature heating program, raise the temperature from room temperature to 600℃ and keep it warm for 2 hours.

[0053] (3) When the temperature reaches 600℃, oxygen is introduced for 5 minutes to ensure that the cavity is an oxygen environment. Then, the nebulizer is turned on and argon is used as the carrier gas to introduce the precursor in the nebulization into the cavity.

[0054] The samples obtained in this embodiment were characterized by XRD phase analysis and SEM characterization of the samples prepared by the fog chemical vapor transport method. The results showed that the samples exhibited a single-crystal orientation with a SnO2 (101) crystal plane. The samples prepared using ethanol showed a rocking curve with a half-width at half-maximum (FWHM) of 0.266°, indicating good crystallinity. The sheet resistance reached 100 kΩ / □, but the thin film grains were large and not very smooth. The table below shows the carrier concentration and mobility of the thin films with different tantalum doping concentrations using ethanol in this embodiment:

[0055] Table 1: Carrier concentration and mobility of thin films with different tantalum doping concentrations using ethanol

[0056]

[0057] Example 2:

[0058] Similar to Example 1, this example uses ethylene glycol to assist in the preparation of Ta-doped tin oxide thin films. The specific steps are as follows:

[0059] (1) Using a mixture of stannous acetate and tantalum pentachloride powder as the source material, weigh 0.4985 g of stannous acetate and 0.0072 g of tantalum pentachloride (atomic ratio 100:1) using an electronic balance, mix them in a beaker, add 10 ml of deionized water to dissolve them into a liquid state, then add 2 ml of concentrated hydrochloric acid and 5-11 ml of ethylene glycol and stir until completely free of precipitate. Then, attach the cleaned R-side sapphire to the sample stage using high-temperature inorganic adhesive. The schematic diagram of the fog chemical vapor deposition system is shown below. Figure 1 As shown.

[0060] (2) Set the temperature heating program, raise the temperature from room temperature to 600℃ and keep it warm for 2 hours.

[0061] (3) When the temperature reaches 600℃, oxygen is introduced for 5 minutes to ensure that the cavity is an oxygen environment. Then, the nebulizer is turned on and argon is used as the carrier gas to introduce the precursor in the nebulization into the cavity.

[0062] The table below shows the carrier concentration and mobility of the thin film with different tantalum doping concentrations using ethylene glycol in this embodiment:

[0063] Table 2: Carrier concentration and mobility of thin films with different tantalum doping concentrations in ethylene glycol

[0064]

[0065] The table below shows the sheet resistance of thin films for different ethanol contents:

[0066] Table 3: Sheet resistance of thin film at different ethanol contents

[0067]

[0068] The table below shows the sheet resistance of thin films under different tantalum doping concentrations:

[0069] Table 4: Sheet resistance of thin films under different tantalum doping concentrations:

[0070]

[0071] The sample obtained in this embodiment was characterized by XRD phase analysis and SEM characterization of the sample prepared by fog chemical vapor deposition. It was found that the sample exhibited a single crystal orientation of SnO2 (101) crystal plane. The rocking curve half width at half maximum of 0.374° of the thin film prepared by ethylene glycol in Example 2 was 0.374°, and the resistivity could also reach 100 kΩ / □. Furthermore, the problems of uneven film and large grain size that occurred when using ethanol for preparation were optimized.

[0072] In Examples 1 and 2, a small amount of hydrochloric acid preferentially reacts with stannous acetate: Sn(CH3COO)2 + 2HCl → SnCl2 + 2CH3COOH. Subsequently, a carrier gas carries the precursor solution into a tube furnace, where the reaction 2Sn(CH3COO)2 + 9O2 → 2SnO2 + 8CO2 + 6H2O (main reaction) occurs, followed by the secondary reaction 2SnCl2 + O2 + 2H2O → 2SnO2 + 4HCl. Simultaneously, 2TaCl5 + 5H2O → Ta2O5 + 10HCl. When tantalum is incorporated into the crystal lattice, the reaction 4(1-x)SnO2 + 2xTa2O5 → 4Sn occurs. 1−x Ta x O2 + xO2. (x is the doping ratio, Ta) 5 ⁺ Replace Sn 4 After ⁺. Each time one Ta is introduced... 5 - Releases one free electron, achieving n-type doping. Key note: The reaction requires sufficient oxygen partial pressure; otherwise, it will lead to Cl... - Residues (forming impurities such as SnOCl) reduce film purity. The temperature must match the precursor decomposition threshold: tin acetate decomposes at temperatures above 300℃, and tantalum pentachloride at 350℃. Too low a temperature will lead to incomplete decomposition, while too high a temperature may cause grain coarsening. The core of the doping reaction is heterovalent substitution (Ta... 5+ →Sn 4+ The high conductivity of thin films is achieved by increasing the concentration of charge carriers (electrons) through charge compensation.

[0073] Example 3:

[0074] This embodiment uses different ethanol contents to grow tin dioxide thin films. The specific steps are as follows:

[0075] (1) Using stannous acetate as the source material, weigh 0.4985 g of stannous acetate using an electronic balance, place it in a beaker, add 10 ml of deionized water, then add 2 ml of concentrated hydrochloric acid to dissolve it, add 0-9 ml of ethanol and stir until there is no precipitate. At the same time, attach the cleaned R-face sapphire to the sample stage using high-temperature inorganic adhesive. The sample stage is placed 6 cm from the air inlet. The schematic diagram of the fog chemical vapor deposition system is shown below. Figure 1 As shown.

[0076] (2) Set the temperature heating program, raise the temperature from room temperature to 650℃ and keep it warm for 2 hours.

[0077] (3) When the temperature reaches 650℃, oxygen is introduced for 5 minutes, the atomizer is turned on to ensure that the cavity is an oxygen environment, and the air is introduced. Nitrogen is used as the carrier gas to introduce the precursor in the atomization into the cavity.

[0078] The sample obtained in this embodiment was characterized by XRD crystal phase analysis of the sample prepared by chemical vapor transport method. It was found that the sample showed a single crystal orientation of SnO2 (101) crystal plane without other impurity peaks. Moreover, the half width at half maximum (WHM) of the rocking curve of the sample prepared by 7.5 ml ethanol reached 0.212°, indicating that the crystal quality of the thin film sample was good.

[0079] Example 4:

[0080] In this embodiment, tin oxide thin films were prepared using different substrate distances under 7.5 ml ethanol conditions. The specific steps are as follows:

[0081] (1) Using stannous acetate as the source material, weigh 0.4985 g of stannous acetate using an electronic balance, place it in a beaker, add 10 ml of deionized water, then add 2 ml of concentrated hydrochloric acid to dissolve it, add 7.5 ml of ethanol and stir until there is no precipitate. At the same time, attach the cleaned R-face sapphire to the self-made sample stage using high-temperature inorganic adhesive. The sample stage is placed 5-8 cm from the air inlet. The schematic diagram of the fog chemical vapor deposition system is shown below. Figure 1 As shown.

[0082] (2) Set the temperature heating program, raise the temperature from room temperature to 650℃ and keep it warm for 2 hours.

[0083] (3) When the temperature reaches 650℃, oxygen is introduced for 5 minutes, the atomizer is turned on to ensure that the cavity is an oxygen environment, and the air is introduced. Nitrogen is used as the carrier gas to introduce the precursor in the atomization into the cavity.

[0084] The sample obtained in this embodiment was characterized by XRD crystal phase analysis of the sample prepared by chemical vapor transport method. It was found that the sample showed a single crystal orientation of SnO2 (101) crystal plane without other impurity peaks. Moreover, the half width at half maximum (WHM) of the rocking curve of the sample prepared with 7.5 ml ethanol and a substrate distance of 7 cm could reach 0.181°, indicating that the crystal quality of the thin film sample was good.

[0085] Example 5:

[0086] In this embodiment, tin oxide thin films were prepared at different temperatures under conditions of 7.5 ml ethanol and a substrate distance of 7 cm. The specific steps are as follows:

[0087] (1) Using stannous acetate as the source material, weigh 0.4985 g of stannous acetate using an electronic balance, place it in a beaker, add 10 ml of deionized water, then add 2 ml of concentrated hydrochloric acid to dissolve it, add 7.5 ml of ethanol and stir until there is no precipitate. At the same time, attach the cleaned R-face sapphire to the sample stage using a high-temperature inorganic adhesive. Place the sample stage 7 cm from the air inlet. The schematic diagram of the fog chemical vapor deposition system is shown below. Figure 1 As shown.

[0088] (2) Set the temperature heating program, raise the temperature from room temperature to 650-850℃ and keep it warm for 2 hours.

[0089] (3) When the temperature reaches 650-850℃, oxygen is introduced for 5 minutes, the atomizer is turned on to ensure that the cavity is an oxygen environment, and the air is introduced. Nitrogen is used as the carrier gas to introduce the precursor in the atomization into the cavity.

[0090] The samples obtained in this embodiment were characterized by XRD phase analysis and SEM characterization. XRD characterization revealed that the samples exhibited a single-crystal orientation of SnO2 (101) crystal plane with no other impurity peaks. Furthermore, the half-width at half-maximum (WHM) of the rocking curve of the samples prepared at 750℃ using 7.5 ml of ethanol and a substrate distance of 7 cm reached 0.159°, indicating a high-quality tin oxide film. SEM surface images showed that the film surface was relatively flat, indicating a regular single-orientation growth pattern. The cross-sectional image showed that the film thickness was approximately 2 μm.

[0091] In Examples 3, 4, and 5, similar to Example 1, a small amount of hydrochloric acid and stannous acetate preferentially react Sn(CH3COO)2 + 2HCl → SnCl2 + 2CH3COOH. Then, the carrier gas carries the precursor solution into the tube furnace where the reaction 2Sn(CH3COO)2 + 9O2 → 2SnO2 + 8CO2 + 6H2O (main reaction) occurs, followed by the secondary reaction 2SnCl2 + O2 + 2H2O → 2SnO2 + 4HCl. Key note: Sufficient oxygen partial pressure is required for the reaction; otherwise, residual Cl and C will occur, reducing the purity of the film.

[0092] This embodiment has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and that the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention.

[0093] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and their tantalum-doped forms, characterized in that, Includes the following steps: S1.

1. Use sapphire to grow tin dioxide thin films. After ultrasonically cleaning the substrate, use high-temperature inorganic adhesive to attach the substrate to the sample stage and place the sample stage in a tube furnace. S1.

2. Stannous acetate and tantalum pentachloride are used as precursors. After weighing, they are placed in a beaker and hydrochloric acid and ethanol / ethylene glycol are added to dissolve stannous acetate and tantalum pentachloride. Deionized water is added to prepare a certain concentration to obtain a colorless and transparent precursor solution. The solution is then placed in the nebulizer container and placed for ultrasonic nebulization. S1.3 After the heating is completed, keep it at the temperature for a period of time, then turn on the atomizer so that the precursor solution is atomized into very small droplets. S1.

4. Two gas streams are introduced: one stream is a carrier gas that guides the atomized precursor solution into the tube furnace, and the other stream is oxygen that is directly introduced into the tube furnace, so that the precursor solution and oxygen react to form a tin oxide film.

2. The fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and their tantalum doping according to claim 1, characterized in that: The purity of stannous acetate and tantalum pentachloride in step S1.2 is not less than 95%, and the atomic ratio of tin to tantalum in the precursor is 99.9:0.1~95:

5.

3. The fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and their tantalum doping according to claim 2, characterized in that: In step S1.3, the atomization power of the atomizer is 1%-100% of the total atomization power.

4. The fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and their tantalum doping according to claim 3, characterized in that: In step S1.4, the tube furnace is heated to the growth deposition temperature and then the film is grown at a constant temperature, wherein the growth deposition temperature is 600℃-700℃.

5. The fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and their tantalum doping according to claim 1, characterized in that: It also includes a method for preparing high-quality tin dioxide single-crystal thin films, the steps of which are: S2.

1. Using sapphire as the heteroepitaxial substrate for growing tin dioxide single crystal thin films, the substrate is ultrasonically cleaned with ethanol and deionized water in sequence, and the substrate surface is dried with high-purity nitrogen to obtain a clean pretreated substrate. The substrate is then attached to the sample stage with high-temperature inorganic adhesive and the sample stage is placed in a tube furnace. S2.2 Using stannous acetate as the tin source, weigh it and put it into a beaker. Add ethanol / ethylene glycol and hydrochloric acid in sequence to fully dissolve the stannous acetate. Add deionized water to prepare a certain concentration to obtain a colorless and transparent precursor solution. Put it into the nebulizer container and wait for sonication. S2.3 After the heating is completed, keep it at the temperature for a period of time, then turn on the atomizer so that the precursor solution is atomized into very small droplets. S2.

4. Two gas streams are introduced. One stream is a carrier gas that introduces the precursor solution, which has been atomized into small droplets, into the tube furnace. The other stream is oxygen, which is directly introduced into the tube furnace to provide part of the oxygen source for thin film deposition and to begin the growth of tin oxide thin film. S2.5 After the reaction is complete, the tin oxide film growth is finished. First, stop the ultrasonic atomization, then turn off the oxygen and stop heating after 3 minutes. Let the substrate cool down to room temperature naturally, and the experimental procedure is over.

6. The fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and their tantalum doping according to claim 5, characterized in that: In step S2.1, the sapphire substrate is a single-crystal preferred-orientation substrate.

7. The fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and their tantalum doping according to claim 6, characterized in that: In step S2.2, the purity of stannous acetate is not less than 95%, and the precursor concentration is 0.01~0.04 mol / L.

8. The fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and their tantalum doping according to claim 5, characterized in that: In step S2.3, the atomization power of the atomizer is 1%-100% of the total atomization power.

9. The fog chemical vapor deposition method for preparing high-quality tin dioxide thin films and their tantalum doping according to claim 8, characterized in that: In step S2.4, the tubular furnace is heated to the growth deposition temperature and then the film is grown at a constant temperature, which is 650℃-850℃.

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