Method for preparing ε-Ga2O3 thin films based on chemical vapor deposition

Abstract

This invention relates to a method for preparing ε-Ga2O3 thin films based on chemical vapor deposition, comprising: placing gallium oxide powder in a heating zone of a quartz tube, and placing a substrate in a deposition zone of the quartz tube; the deposition zone and the heating zone are integrally connected and communicate with each other; a predetermined first distance is maintained between the substrate and the heating zone; a mixture of carrier gas and hydrogen is introduced from one end of the heating zone of the quartz tube; the proportion of hydrogen in the mixture is 5%-10%; the heating zone of the quartz tube is heated to a predetermined temperature under normal pressure and held at the predetermined temperature for a predetermined time, so that the gallium oxide powder is reduced to gallium vapor and water vapor under the action of hydrogen, and at the same time, the gallium vapor and water vapor generate gallium hydroxide and hydrogen in the deposition zone with the flow of the mixture gas, and then the gallium hydroxide is thermally decomposed and deposited on the substrate in the deposition zone, followed by annealing to obtain an ε-Ga2O3 thin film; wherein the predetermined temperature of the heating zone is 900℃-1200℃; and the temperature of the deposition zone is 500℃-850℃.

Description

Technical Field

[0001] This invention relates to the field of nanomaterials technology, and in particular to a method for preparing ε-Ga2O3 thin films based on chemical vapor deposition. Background Technology

[0002] Gallium oxide (GaO) is a wide-bandgap semiconductor with a bandgap of Eg = 4.9 eV. It exhibits excellent conductivity and luminescence properties, making it a promising candidate for applications in optoelectronic devices. It is used as an insulating layer in Ga-based semiconductor materials and in ultraviolet filters. These are traditional applications of gallium oxide, but its future applications in power, especially high-power applications, are even more anticipated.

[0003] Ga₂O₃ semiconductor materials have five different structures: α-, β-, γ-, δ-, and ε-. The most stable Ga₂O₃ structure is β-Ga₂O₃, and other Ga₂O₃ structures can be transformed into β-Ga₂O₃ by changing the conditions. Among them, the metastable ε-Ga₂O₃ crystal exhibits a pseudo-hexagonal orthorhombic crystal system, characterized by a large band gap, high phase transition temperature, spontaneous polarization, and good thermodynamic stability. Furthermore, its non-inverted symmetry along the c-axis and ferroelectric properties have gradually attracted considerable attention in the research of high electron mobility transistors (HEMTs) and ferroelectric devices.

[0004] Currently, most methods for growing gallium oxide thin films by chemical vapor deposition use metallic gallium as the gallium source and oxygen as the oxygen source. The problem with this method is that metallic gallium is easily oxidized in air and is not easy to store. At room temperature, metallic gallium is in a liquid state, making it difficult to accurately measure and use it. Furthermore, the gallium oxide thin films produced are mostly stable β-Ga2O3 gallium oxide thin films. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a method for preparing ε-Ga2O3 thin films based on chemical vapor deposition. This method uses solid gallium oxide as a raw material, eliminating the problems of difficulty in storage and handling caused by using liquid metallic gallium as a raw material, and can also generate metastable ε-Ga2O3 thin films.

[0006] To achieve the above objectives, the present invention provides a method for preparing ε-Ga2O3 thin films based on chemical vapor deposition, the method comprising:

[0007] Gallium oxide powder is placed in the heating zone of a quartz tube, and a substrate is placed in the deposition zone of the quartz tube; the deposition zone and the heating zone are integrally connected and communicate with each other; a predetermined first distance is maintained between the substrate and the heating zone;

[0008] A mixture of carrier gas and hydrogen is introduced from one end of the heating zone of the quartz tube; the proportion of hydrogen in the mixture is 5%-10%.

[0009] Under normal pressure, the heating zone of the quartz tube is heated to a preset temperature and held at the preset temperature for a preset time, so that the gallium oxide powder is reduced to gallium vapor and water vapor under the action of hydrogen gas. At the same time, the gallium vapor and water vapor are generated in the deposition zone by the gas flow of the mixed gas to form gallium hydroxide and hydrogen gas. The gallium hydroxide is thermally decomposed and deposited on the substrate of the deposition zone. After annealing, an ε-Ga2O3 thin film is obtained. The preset temperature of the heating zone is 900℃-1200℃; the temperature of the deposition zone is 500℃-850℃.

[0010] Preferably, the substrate includes a sapphire substrate, a fluorine crystal cloud substrate, or a quartz substrate.

[0011] Preferably, the preset first distance is 3 cm to 5 cm.

[0012] Preferably, there is a preset height difference between the substrate and the gallium oxide powder; the preset height difference is 1 cm to 2 cm.

[0013] Preferably, there is a preset second distance between the substrate and the gallium oxide powder; the preset second distance is 5 cm to 40 cm.

[0014] Preferably, the gas flow rate of the mixed gas is 60 sccm-100 sccm.

[0015] Preferably, the carrier gas includes any one or both of nitrogen and argon.

[0016] Preferably, the heating rate is 22-28°C / minute, and the preset duration is 20-90 minutes.

[0017] Preferably, the annealing atmosphere includes any one of nitrogen, argon, air, or vacuum.

[0018] The present invention provides a method for preparing ε-Ga2O3 thin films based on chemical vapor deposition. This method uses gallium oxide powder as raw material, overcoming the problems of difficulty in storing and handling metallic gallium. By introducing a certain proportion of hydrogen gas at a certain gas flow rate to reduce gallium oxide powder, on the one hand, solid gallium oxide can be used for chemical vapor deposition; on the other hand, gallium vapor flows towards the substrate under the influence of the gas flow. By adjusting the position of the substrate and the heating zone, the deposition temperature can be changed, allowing gallium vapor to react with water vapor to generate gallium hydroxide. The gallium hydroxide decomposes upon heating and is deposited, thereby obtaining the ε-Ga2O3 thin film. This reduces the temperature requirements of gallium vaporization for the chemical vapor deposition process. Attached Figure Description

[0019] Figure 1 This is a flowchart of a method for preparing ε-Ga2O3 thin films based on chemical vapor deposition, provided in an embodiment of the present invention.

[0020] Figure 2 This is a schematic diagram showing the positional relationship between the substrate and gallium oxide powder provided in an embodiment of the present invention;

[0021] Figure 3 This is a SEM image of the ε-Ga2O3 thin film provided in Example 2 of the present invention;

[0022] Figure 4 This is a SEM image of the ε-Ga2O3 thin film provided in Example 3 of the present invention;

[0023] Figure 5 AFM image of the ε-Ga2O3 thin film provided in Example 2 of this invention;

[0024] Figure 6 The images are XRD images of the ε-Ga2O3 thin films provided in Examples 1-3 of this invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0027] This invention provides a method for preparing ε-Ga2O3 thin films based on chemical vapor deposition, specifically including the following: Figure 1 The steps shown are as follows:

[0028] Step 110: Place gallium oxide powder in the heating zone of the quartz tube and place the substrate in the deposition zone of the quartz tube.

[0029] Combination Figure 2 As shown, the deposition zone and heating zone of the quartz tube are integrally connected and interconnected. The temperature of the deposition zone is lower than that of the heating zone. The specific dimensions of the quartz tube are: inner diameter 47mm, outer diameter 50mm, and length 1000mm.

[0030] The substrate can specifically include a sapphire substrate, a fluorine crystal substrate, or a quartz substrate. Among the isomers of Ga2O3 thin films, the metastable structure is ε-Ga2O3. Different Ga2O3 thin films with different structures can be obtained under different growth conditions, and ε-Ga2O3 and the other isomers can be converted to β-Ga2O3 under suitable conditions. However, the growth conditions for the metastable ε-Ga2O3 thin film are much more demanding than those for β-Ga2O3, and controlling the deposition temperature is crucial for the formation of ε-Ga2O3. The temperature of the deposition zone can specifically be 500℃-850℃. Therefore, a predetermined first distance is maintained between the substrate and the heating zone to ensure the deposition temperature, allowing the gas in the heating zone to deposit better on the substrate and ensuring that ε-Ga2O3 is deposited. The predetermined first distance can specifically be 3 cm-5 cm, preferably 4 cm.

[0031] Because the gas distribution in the heating zone is uneven within the quartz tube, with most of it concentrated at the top, a predetermined height difference is maintained between the substrate and the gallium oxide powder in a preferred embodiment to ensure the final thickness of the ε-Ga₂O₃ thin film. This predetermined height difference can be 1-2 cm, preferably 1.5 cm. This height difference can be achieved by adding a support structure under the substrate, or by other methods; this application does not specifically limit the method used.

[0032] To ensure that the gallium oxide powder is completely vaporized in the heating zone before deposition on the substrate, in another preferred embodiment, a predetermined second distance is maintained between the substrate and the gallium oxide powder. This predetermined second distance can specifically be 5 cm to 40 cm, preferably 15 cm.

[0033] To ensure the purity of the formed ε-Ga₂O₃ film, in another preferred embodiment, the substrate is cleaned before being placed into the quartz tube. The cleaning process can be performed by ultrasonic cleaning with acetone, ethanol, and deionized water in sequence. After cleaning, the substrate is dried under a nitrogen atmosphere.

[0034] The purity of gallium oxide powder is not less than 99.99%.

[0035] Because gallium is easily oxidized in air and difficult to preserve, and because gallium has a very low melting point and is liquid at room temperature, it is difficult to accurately measure its quantity. Using gallium oxide powder as a raw material overcomes the problems of difficulty in preserving and using gallium as a raw material.

[0036] Step 120: A mixture of carrier gas and hydrogen is introduced from one end of the heating zone of the quartz tube.

[0037] Specifically, the proportion of hydrogen in the mixed gas is 5%-10%, preferably 10%. The gas flow rate of the mixed gas can be 60 sccm-100 sccm. The carrier gas can specifically include any one or both of nitrogen and argon.

[0038] In a hydrogen-rich environment, gallium vapor can overcome its tendency to crystallize towards thermodynamic stability. This is due to the combined effects of temperature and hydrogen content. Temperature controls the average kinetic energy of the molecules and the thermodynamic phase transition, while hydrogen content controls the number of dangling bonds occupied by hydrogen ions. Hydrogen's electronegativity is closer to that of gallium. At higher hydrogen content, hydrogen ions will occupy some dangling bonds. Compared to octahedral coordination, tetrahedral coordination dangling bonds are more stable. Hydrogen ions preferentially occupy tetrahedral coordination dangling bonds, making it easier for octahedral coordination gallium-oxygen bonds to form. Macroscopically, the number of octahedral coordinations of gallium increases, leading to its tendency to grow towards ε-Ga₂O₃. After nucleation and island formation, the temperature does not reach the phase transition requirement, thus overcoming the tendency to transition to thermodynamic stability and forming a metastable state.

[0039] Step 130: Under normal pressure, the heating zone of the quartz tube is heated to a preset temperature and held at the preset temperature for a preset time, so that the gallium oxide powder is reduced into gallium vapor and water vapor under the action of hydrogen. At the same time, the gallium vapor and water vapor are generated into gallium hydroxide and hydrogen in the deposition zone with the airflow of the mixed gas. The gallium hydroxide is thermally decomposed and deposited on the substrate in the deposition zone. After annealing, an ε-Ga2O3 thin film is obtained.

[0040] Specifically, the heating rate is 22-28℃ / min, preferably 28℃ / min. The preset temperature is 900℃-1200℃, preferably 1000℃-1200℃. The preset duration is 20-90 minutes, preferably 40-50 minutes. Since gallium has a very high boiling point of 2403℃, and the current chemical vapor deposition (CVD) process temperature is limited, generally not exceeding 1600℃, it is impossible to vaporize gallium using CVD. Therefore, this application uses hydrogen to reduce gallium oxide powder. On the one hand, solid gallium oxide can be used for CVD; on the other hand, the generated gallium vapor moves towards the substrate under the influence of the gas flow, meaning that gallium can reach the substrate for deposition without vaporization, reducing the temperature requirements of the CVD process for gallium vaporization. The specific reaction chemical equation is as follows:

[0041] Ga2O3(s)+3H2(g)=2Ga(g)+3H2O(g)

[0042] 2Ga(g)+6H2O(g)=2Ga(OH)3(g)+3H2(g)

[0043] 2Ga(OH)3(g)=Ga2O3(s)+3H2O(g)

[0044] Annealing can be achieved by allowing the quartz tube to naturally cool to room temperature as the temperature of the tube furnace decreases; alternatively, the insulation cover of the tube furnace can be opened during the temperature drop process to expose the quartz tube for cooling.

[0045] The annealing atmosphere specifically includes any one of nitrogen, argon, air, or vacuum.

[0046] In an alternative approach, after step 130, a purification process can be performed depending on the selected substrate. For example, when the substrate is a fluorine crystal cloud, purification is not applicable due to the two-dimensional structure of the fluorine crystal cloud.

[0047] The impurity removal process can specifically involve repeated application of release tape, polypropylene carbonate (PPC) tape, polysiloxane (PDMS) tape, or ordinary tape. The purpose of impurity removal is to remove gallium oxide nanoribbons generated on the surface of the ε-Ga₂O₃ thin film.

[0048] The present invention provides a method for preparing ε-Ga2O3 thin films based on chemical vapor deposition. This method uses gallium oxide powder as raw material, overcoming the problems of difficulty in storing and handling metallic gallium. By introducing a certain proportion of hydrogen gas at a certain gas flow rate to reduce gallium oxide powder, on the one hand, solid gallium oxide can be used for chemical vapor deposition; on the other hand, gallium vapor flows towards the substrate under the influence of the gas flow. By adjusting the position of the substrate and the heating zone, the deposition temperature can be changed, allowing gallium vapor to react with water vapor to generate gallium hydroxide. The gallium hydroxide decomposes upon heating and is deposited, thereby obtaining the ε-Ga2O3 thin film. This reduces the temperature requirements of gallium vaporization for the chemical vapor deposition process.

[0049] To better understand the technical solution provided by the present invention, the preparation process of ε-Ga2O3 thin films is illustrated below with several specific examples.

[0050] Example 1

[0051] Step 1: Take 0.2g of gallium oxide powder with a purity of 99.99% and place it in the heating zone of the quartz tube. Take a sapphire substrate with a thickness of 430μm, a surface roughness of ≤10nm, and a size of 2cm×2cm. Clean it ultrasonically with acetone, anhydrous ethanol, and deionized water in sequence, three times with each cleaning agent. Then, dry it at 60℃ under a nitrogen atmosphere for half an hour. After cooling, place it in the deposition zone of the quartz tube. The distance between the substrate and the heating zone is 4cm, and the horizontal distance between the substrate and the gallium oxide powder is 15cm. Place a quartz sheet under the substrate so that the height of the substrate is 1.5cm higher than that of the gallium oxide powder.

[0052] Step 2: Introduce a mixture of argon and hydrogen gas into one end of the heating zone of the quartz tube. The hydrogen content is 10%, and the gas flow rate is 100 sccm.

[0053] Step 3: Under normal pressure, the quartz tube is heated at a rate of 28°C / min until the temperature of the heated zone reaches 1100°C. This temperature is maintained at 1100°C for 40 minutes, allowing the gallium oxide powder to be reduced into gallium vapor and water vapor under the action of hydrogen gas. Simultaneously, the gallium vapor and water vapor react in the deposition zone at a temperature of 750°C to generate gallium hydroxide. The gallium hydroxide decomposes and deposits on the substrate to obtain an ε-Ga₂O₃ thin film.

[0054] Step 4: Introduce argon gas into the quartz tube. Under the argon atmosphere, allow the quartz tube to cool down naturally to room temperature, and then remove the ε-Ga2O3 film.

[0055] Step 5: Apply release tape to the surface of the ε-Ga2O3 film 5 times to remove gallium oxide nanoribbons generated on the surface.

[0056] Example 2

[0057] Step 1: Take 0.2g of gallium oxide powder with a purity of 99.99% and place it in the heating zone of the quartz tube. Take a sapphire substrate with a thickness of 430μm, a surface roughness of ≤10nm, and a size of 2cm×2cm. Clean it ultrasonically with acetone, anhydrous ethanol, and deionized water in sequence, three times with each cleaning agent. Then, dry it at 60℃ under a nitrogen atmosphere for half an hour. After cooling, place it in the deposition zone of the quartz tube. The distance between the substrate and the heating zone is 4cm, and the horizontal distance between the substrate and the gallium oxide powder is 15cm. Place a quartz sheet under the substrate so that the height of the substrate is 1.5cm higher than that of the gallium oxide powder.

[0058] Step 2: Introduce a mixture of argon and hydrogen gas into one end of the heating zone of the quartz tube. The hydrogen content is 10%, and the gas flow rate is 60 sccm.

[0059] Step 3: Under normal pressure, the quartz tube is heated at a rate of 28°C / min until the temperature of the heated zone reaches 1100°C. This temperature is maintained at 1100°C for 40 minutes, allowing the gallium oxide powder to be reduced into gallium vapor and water vapor under the action of hydrogen gas. Simultaneously, the gallium vapor and water vapor react in the deposition zone at a temperature of 750°C to generate gallium hydroxide. The gallium hydroxide decomposes and deposits on the substrate to obtain an ε-Ga₂O₃ thin film.

[0060] Step 4: Introduce argon gas into the quartz tube. Under the argon atmosphere, allow the quartz tube to cool down naturally to room temperature, and then remove the ε-Ga2O3 film.

[0061] Step 5: Apply release tape to the surface of the ε-Ga2O3 film 5 times to remove gallium oxide nanoribbons generated on the surface.

[0062] Example 3

[0063] Step 1: Take 0.2g of gallium oxide powder with a purity of 99.99% and place it in the heating zone of the quartz tube. Take a sapphire substrate with a thickness of 430μm, a surface roughness of ≤10nm, and a size of 2cm×2cm. Clean it ultrasonically with acetone, anhydrous ethanol, and deionized water in sequence, three times with each cleaning agent. Then, dry it at 60℃ under a nitrogen atmosphere for half an hour. After cooling, place it in the deposition zone of the quartz tube. The distance between the substrate and the heating zone is 4cm, and the horizontal distance between the substrate and the gallium oxide powder is 15cm. Place a quartz sheet under the substrate so that the height of the substrate is 1.5cm higher than that of the gallium oxide powder.

[0064] Step 2: Introduce a mixture of argon and hydrogen gas into one end of the heating zone of the quartz tube. The hydrogen content is 10%, and the gas flow rate is 80 sccm.

[0065] Step 3: Under normal pressure, the quartz tube is heated at a rate of 28°C / min until the temperature of the heated zone reaches 1100°C. This temperature is maintained at 1100°C for 40 minutes, allowing the gallium oxide powder to be reduced into gallium vapor and water vapor under the action of hydrogen gas. Simultaneously, the gallium vapor and water vapor react in the deposition zone at a temperature of 750°C to generate gallium hydroxide. The gallium hydroxide decomposes and deposits on the substrate to obtain an ε-Ga₂O₃ thin film.

[0066] Step 4: Introduce argon gas into the quartz tube. Under the argon atmosphere, allow the quartz tube to cool down naturally to room temperature, and then remove the ε-Ga2O3 film.

[0067] Step 5: Apply release tape to the surface of the ε-Ga2O3 film 5 times to remove gallium oxide nanoribbons generated on the surface.

[0068] The detection results of the ε-Ga2O3 thin film prepared by the above method are as follows: Figure 3-6 As shown.

[0069] When the ratio of hydrogen to carrier gas is fixed, such as Figure 3 The image shown is a SEM image of the ε-Ga2O3 thin film prepared in Example 2, where the presence of hexagonal islands can be clearly seen. Figure 5 The image shown is an AFM image of the ε-Ga2O3 thin film prepared in Example 2, with a surface roughness of 8.09. Figure 4The image shown is a SEM image of the ε-Ga2O3 film prepared in Example 3. It can be seen that the surface is smooth and all islands are fully connected. This indicates that the gas flow rate has a certain influence on the smoothness of the final ε-Ga2O3 film.

[0070] Figure 6 The XRD results of the ε-Ga2O3 films prepared in Examples 1, 2 and 3 show that the three diffraction peaks correspond to the (0002), (0004) and (0006) peaks of ε-Ga2O3, respectively.

[0071] Example 4

[0072] Step 1: Take 0.2g of gallium oxide powder with a purity of 99.99% and place it in the heating zone of the quartz tube. Take a 1cm×1cm fluorine crystal cloud substrate with a thickness of 100μm and a surface roughness ≤0.65nm, and ultrasonically clean it sequentially with acetone, anhydrous ethanol, and deionized water, three times with each cleaning agent. Then, dry it for half an hour at 60℃ under a nitrogen atmosphere. After cooling, place it in the deposition zone of the quartz tube. The distance between the substrate and the heating zone is 3cm, and the horizontal distance between the substrate and the gallium oxide powder is 40cm. Place a quartz sheet under the substrate so that the height of the substrate is 1.0cm higher than that of the gallium oxide powder.

[0073] Step 2: Introduce a mixture of nitrogen and hydrogen gas into one end of the heating zone of the quartz tube. The hydrogen content is 5%, and the gas flow rate is 100 sccm.

[0074] Step 3: Under normal pressure, the quartz tube is heated at a rate of 22°C / min until the temperature of the heated zone reaches 1200°C. This temperature is maintained at 1200°C for 50 minutes, allowing the gallium oxide powder to be reduced into gallium vapor and water vapor under the action of hydrogen gas. Simultaneously, the gallium vapor and water vapor react in the deposition zone at a temperature of 850°C to generate gallium hydroxide. The gallium hydroxide decomposes and deposits on the substrate to obtain an ε-Ga₂O₃ thin film.

[0075] Step 4: Introduce nitrogen gas into the quartz tube. Under the nitrogen atmosphere, allow the quartz tube to cool down naturally to room temperature, and then remove the ε-Ga2O3 film.

[0076] Step 5: Apply polysiloxane PDMS tape to the surface of the ε-Ga2O3 film 5 times to remove the gallium oxide nanoribbons generated on the surface.

[0077] Example 5

[0078] Step 1: Take 0.2g of gallium oxide powder with a purity of 99.99% and place it in the heating zone of the quartz tube. Take a 1cm×1cm fluorine crystal cloud substrate with a thickness of 100μm and a surface roughness ≤0.65nm, and ultrasonically clean it sequentially with acetone, anhydrous ethanol, and deionized water, three times with each cleaning agent. Then, dry it for half an hour at 60℃ under a nitrogen atmosphere. After cooling, place it in the deposition zone of the quartz tube. The distance between the substrate and the heating zone is 5cm, and the horizontal distance between the substrate and the gallium oxide powder is 5cm. Place a quartz sheet under the substrate so that the height of the substrate is 2.0cm higher than that of the gallium oxide powder.

[0079] Step 2: Introduce a mixture of nitrogen and hydrogen gas into one end of the heating zone of the quartz tube. The hydrogen content is 10%, and the gas flow rate is 80 sccm.

[0080] Step 3: Under normal pressure, the quartz tube is heated at a rate of 26°C / min until the temperature of the heated zone reaches 900°C. This temperature is maintained at 900°C for 20 minutes, allowing the gallium oxide powder to be reduced into gallium vapor and water vapor under the action of hydrogen gas. Simultaneously, the gallium vapor and water vapor react in the deposition zone at a temperature of 500°C to generate gallium hydroxide. The gallium hydroxide decomposes and deposits on the substrate to obtain an ε-Ga₂O₃ thin film.

[0081] Step 4: Pass air into the quartz tube. Under the air atmosphere, open the heat preservation cover of the tube furnace to allow the quartz tube to cool down to room temperature, and then remove the ε-Ga2O3 film.

[0082] Step 5: Apply ordinary adhesive tape to the surface of the ε-Ga2O3 film 5 times to remove the gallium oxide nanoribbons generated on the surface.

[0083] Example 6

[0084] Step 1: Take 0.2g of gallium oxide powder with a purity of 99.99% and place it in the heating zone of the quartz tube. Take a quartz substrate with a thickness of 500μm and a size of 2cm×2cm, and ultrasonically clean it sequentially with acetone, anhydrous ethanol, and deionized water, three times with each cleaning agent. Then, dry it for half an hour at 60℃ under a nitrogen atmosphere. After cooling, place it in the deposition zone of the quartz tube. The distance between the substrate and the heating zone is 3.5cm, and the horizontal distance between the substrate and the gallium oxide powder is 30cm. Place a quartz sheet under the substrate so that the height of the substrate is 1.5cm higher than that of the gallium oxide powder.

[0085] Step 2: Introduce a mixture of nitrogen and hydrogen gas into one end of the heating zone of the quartz tube. The hydrogen content is 8%, and the gas flow rate is 60 sccm.

[0086] Step 3: Under normal pressure, the quartz tube is heated at a rate of 25°C / min until the temperature of the heated zone reaches 1000°C. This temperature is maintained at 1000°C for 90 minutes, allowing the gallium oxide powder to be reduced into gallium vapor and water vapor under the action of hydrogen gas. Simultaneously, the gallium vapor and water vapor react in the deposition zone at a temperature of 800°C to generate gallium hydroxide. The gallium hydroxide decomposes and deposits on the substrate to obtain an ε-Ga₂O₃ thin film.

[0087] Step 4: Evacuate the quartz tube and allow it to cool naturally to room temperature under vacuum. Then, remove the ε-Ga2O3 thin film.

[0088] Step 5: Apply polypropylene carbonate (PPC) tape to the surface of the ε-Ga2O3 film four times to remove gallium oxide nanoribbons generated on the surface.

[0089] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for producing an ε-Ga2O3 thin film based on a chemical vapor deposition method, characterized by, The method comprises: Placing gallium oxide powder in a heating zone of a quartz tube, and placing a substrate in a deposition zone of the quartz tube; the deposition zone and the heating zone are integrally connected and communicated; the substrate has a preset first distance from the heating zone; A mixed gas of carrier gas and hydrogen gas is introduced from one end of the heating zone of the quartz tube; the proportion of the hydrogen gas in the mixed gas is 5%-10%; the gas flow of the mixed gas is 60sccm-100sccm; Under normal pressure, the heating zone of the quartz tube is heated to a preset temperature, and is kept at the preset temperature for a preset time length, so that the gallium oxide powder is reduced into gallium vapor and water vapor under the action of hydrogen gas; meanwhile, the gallium vapor and the water vapor generate gallium hydroxide and hydrogen gas in the deposition zone along with the gas flow of the mixed gas; the gallium hydroxide is decomposed and deposited on the substrate in the deposition zone by heating, and then is subjected to annealing treatment to obtain an ε-Ga2O3 thin film; wherein the preset temperature of the heating zone is 900-1200℃; the temperature of the deposition zone is 500-850℃.

2. The method of claim 1, wherein, The substrate comprises a sapphire substrate, a fluorite wafer substrate or a quartz substrate.

3. The method of claim 1, wherein, The preset first distance is 3-5cm.

4. The method of claim 1, wherein, The substrate has a preset height difference from the gallium oxide powder; the preset height difference is 1-2cm.

5. The method of claim 1, wherein, The substrate has a preset second distance from the gallium oxide powder; the preset second distance is 5-40cm.

6. The method of claim 1, wherein, The carrier gas comprises any one or both of nitrogen and argon.

7. The method of claim 1, wherein, The heating rate is 22-28℃ / min, and the preset time length is 20-90min.

8. The method of claim 1, wherein, The annealing atmosphere comprises any one of nitrogen, argon, air or vacuum.

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