In-situ annealing device and method for (AlxGa1-x) 2O3 film

Abstract

The invention relates to the technical field of semiconductor thin film material manufacturing, in particular to an in-situ annealing device and method for an (Al < x > Ga < 1-x >) 2O3 thin film. The in-situ annealing device comprises a deposition chamber and an annealing assembly; a target table and a bottom support are arranged in the deposition chamber, and a set gap is formed between the target table and the bottom support; the annealing assembly comprises a rotating shaft, a front heating disc and a baffle, the rotating shaft is rotationally installed on the deposition chamber, the front heating disc and the baffle are installed at different circumferential angles of the inner end of the rotating shaft and located between the target table and the bottom support, the rotating shaft is a hollow pipe, an air outlet hole is formed in the front heating disc, and the air outlet hole is communicated with the baffle. And the hollow pipe is communicated with the air outlet hole and is used for introducing inert gas into the deposition chamber. According to the invention, in-situ annealing is realized, pollution in a film transfer process is avoided, and heating uniformity during annealing is improved, so that film defects are reduced, and film quality is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic special material manufacturing, in particular to an (Al x Ga 1-x )2O3 thin film in-situ annealing device and method. Background Art

[0002] At present, the preparation technology of electronic special materials is developing in the direction of high purity and multifunctionality. For example, high-purity cobalt targets, nickel-platinum alloy targets and other materials are widely used in the manufacture of high-end electronic devices such as integrated circuits and memories due to their excellent conductivity and corrosion resistance. However, these traditional metal targets have limitations in emerging fields such as wide bandgap semiconductors and ultraviolet optoelectronic devices. Their bandgap width is difficult to flexibly control, and their stability in high temperature environments is insufficient. In contrast, (Al x Ga 1-x )2O3 thin films can achieve continuous changes in bandgap width through composition adjustment, while also having high breakdown field strength and thermal stability, making them ideal candidate materials for the next generation of power electronics and deep ultraviolet optoelectronic devices.

[0003] (Al x Ga 1-x )2O3 is a ternary alloy composed of gallium oxide and aluminum oxide. Since aluminum and gallium belong to the same main group and gallium oxide and aluminum oxide have certain similarities in crystal structure, they can form a solid solution in any proportion. Its band gap can be changed according to the change of aluminum component value x. When x increases from 0 to 1, (Al x Ga 1-x The band gap of )2O3 is adjusted from 4.8eV to 7.2eV. Therefore, by doping aluminum oxide into gallium oxide, the absorption edge of gallium oxide can be extended from the solar-blind band to the vacuum ultraviolet band. At the same time, the breakdown field strength of gallium oxide is further improved, making this material valuable in the fields of photoelectric detection and power electronic devices.

[0004] (Al x Ga 1-x )2O3 thin film preparation methods include pulsed laser deposition, magnetron sputtering deposition, atomized chemical vapor deposition, etc. Among them, pulsed laser deposition and magnetron sputtering deposition belong to physical vapor deposition methods. The principle is to use laser or particles to ablate or bombard the ternary alloy target of gallium oxide and aluminum oxide to produce elemental particles required for thin film growth. These particles then undergo collision, adsorption, nucleation, diffusion, growth and other processes on the substrate to eventually form a film. Atomized chemical vapor deposition belongs to the chemical vapor deposition method. The specific principle is that after the gallium acetylacetonate and aluminum acetylacetonate solutions are atomized, a chemical reaction occurs, the organic groups become small molecules such as water, carbon dioxide, etc. and leave, and the metal atoms remain on the substrate to form a film.

[0005] However, whether it is physical vapor deposition or chemical vapor deposition methods, it is inevitable to generate defects in the (Al x Ga 1-x )2O3 thin film. One of the reasons is that the radii of aluminum ions and gallium ions are different. When aluminum replaces part of gallium and is incorporated into the gallium oxide lattice, lattice distortion will occur. When this lattice distortion accumulates to a certain extent, stress will be generated in the thin film, which is one of the sources of defect generation. Currently, to address the defects caused by lattice distortion, the most commonly used method is to anneal the sample. By using high temperature to change the positions of atoms, the atoms are rearranged and relaxed inside the lattice, releasing the stress, thereby eliminating or minimizing the defects.

[0006] However, the commonly used annealing method at present is to take out the sample from the growth chamber and transfer it to the annealing equipment for annealing after cooling to room temperature at the end of thin film growth. This process is rather cumbersome and time-consuming, and the thin film is easily contaminated during the transfer process, thus affecting its quality. At the same time, the commonly used annealing equipment currently includes box-type annealing furnaces and tube-type annealing furnaces. The heating area is relatively large compared with the sample, and uneven heating may occur depending on the position where the sample is placed.

[0007] Therefore, the prior art has the following technical problems:

[0008] ① Complicated process and pollution risk: The thin film needs to go through multiple steps of "growth → cooling → transfer → annealing" operations, which is time-consuming and increases the probability of sample contamination. Especially during the transfer process, impurities may be adsorbed or surface oxidation may occur.

[0009] ② Poor heat uniformity: The heating area of traditional annealing equipment is much larger than the sample size, and the placement position of the sample affects the thermal field distribution, resulting in a significant temperature gradient and easily generating thermal stress, which exacerbates the thin film defects.

[0010] ③ Insufficient equipment compatibility: The existing annealing equipment is separated from the thin film growth equipment, and in-situ annealing cannot be achieved. Operations such as repeated vacuum pumping and heating are required, resulting in low efficiency and high energy consumption. Summary of the Invention

[0011] The present invention aims to solve the problems of cumbersome annealing process, easy contamination, and uneven heating of the existing (Al x Ga 1-x )2O3 thin film. By improving the heating system of the pulsed laser deposition equipment and introducing a pre-heating plate to achieve in-situ annealing, contamination during the thin film transfer process is avoided, and the heat uniformity during annealing is improved, thereby reducing thin film defects and improving the thin film quality.

[0012] To achieve the above object, the embodiments of the present invention provide the following technical solutions:

[0013] A kind of (Alx Ga 1-x )2O3 thin film in-situ annealing device, comprising: a deposition chamber and an annealing assembly; a target table and a base are provided in the deposition chamber, and a set gap is provided between the target table and the base; the annealing assembly comprises a rotating shaft, a front heating plate and a baffle, the rotating shaft is rotatably mounted on the deposition chamber, the front heating plate and the baffle are mounted at different circumferential angles on the inner end of the rotating shaft, and the front heating plate and the baffle are located between the target table and the base, the rotating shaft is a hollow tube, an air outlet is provided on the front heating plate, a gas dispersion network is provided in the air outlet, and the hollow tube is connected to the air outlet for introducing inert gas into the deposition chamber.

[0014] Optionally, an electric heating wire is installed on the front heating plate, and the electric heating wire is coiled on the end surface of the front heating plate where the air outlet is provided.

[0015] Optionally, the annealing assembly further includes a handle, which is connected to the rotating shaft and fixed with a fixing screw, and a gas valve for switching on and off inert gas is provided at the outer end of the rotating shaft.

[0016] Optionally, a target material is provided on the side of the target stage facing the base, and a substrate is provided on the side of the base facing the target stage.

[0017] Optionally, the front heating plate has a diameter of 75 mm, and when the front heating plate is lowered, it is parallel to the bottom support with a spacing of 5 mm.

[0018] The embodiment of the present invention also provides a method as described above (Al x Ga 1-x )2O3 thin film in-situ annealing method, comprising the following steps:

[0019] After completing thin film deposition in a pulsed laser deposition device, the sample is kept on the bottom support of the deposition chamber;

[0020] Rotate the rotating shaft to lower the front heating plate to form a parallel structure with the bottom support, and the front heating plate is connected to the inert gas supply system through a hollow tube;

[0021] Activate the heating elements of the bottom support and the front heating plate to form a double-sided heating structure, set the heating temperature range and start the inert gas supply to perform in-situ annealing of the film;

[0022] After maintaining the predetermined annealing time, the heating system and gas supply are turned off, and the annealed film is removed after the chamber cools naturally.

[0023] Optionally, the heating temperature range is 700-800°C.

[0024] Optionally, the annealing time is 30-60 minutes.

[0025] Optionally, the inert gas is nitrogen.

[0026] Optionally, the thin film deposition is completed in a pulsed laser deposition device, including:

[0027] Prepare a sapphire substrate;

[0028] Place the target and the substrate on the target stage and the susceptor respectively, fasten them with screws and then put them into the deposition chamber. The distance between the target and the substrate is 4.7 - 10 cm;

[0029] Use a mechanical pump and a molecular pump to evacuate the chamber to 7×10-5 Pa, set the substrate heating temperature to 600 - 680 °C, introduce high-purity oxygen, and control the oxygen pressure in the deposition chamber at 1 Pa;

[0030] After the chamber environment is stable, first perform pre-targeting to remove contaminants on the target surface, and then use pulsed laser ablation of the target for deposition. The laser wavelength is 248 nm, the energy of a single pulsed laser is 150 - 450 mJ, the frequency is 3 - 10 Hz, and the number of pulses is 10800 - 36000.

[0031] One or more technical solutions provided in the embodiments of the present invention have at least the following technical effects or advantages:

[0032] 1. The in-situ annealing device includes a deposition chamber and an annealing component. The deposition chamber is provided with a target stage and a susceptor, and a specific gap is reserved between the two to accommodate the thin film growth space. The annealing component includes a rotating shaft, a front heating plate and a baffle. The rotating shaft realizes the position switching of the front heating plate and the baffle between the target stage and the susceptor through rotation. The front heating plate and the baffle are fixed at different circumferential angles of the rotating shaft. When the rotating shaft rotates, the front heating plate can descend to near the susceptor to form an annealing heating area. The rotating shaft is designed as a hollow tube, which is connected to the air outlet holes on the front heating plate, and an inert gas is transported to the chamber through this pipeline. Through this device, double-sided heating of the thin film and inert gas protection are realized during the annealing process, avoiding the pollution problem caused by sample transfer in the traditional annealing process. At the same time, the temperature uniformity is improved through the compact layout of the heating plates.

[0033] 2. Through this in-situ annealing method, the annealing process is simplified: by improving the heating system of the thin film growth device, annealing is directly completed in the deposition chamber, eliminating the sample transfer link, avoiding pollution and improving efficiency; the heat uniformity is improved: a double-sided heating design (the susceptor and the front heating plate work together) is adopted, the distance between the heating area and the sample is reduced (such as 5 mm), a uniform thermal field distribution is realized, and the thermal stress is reduced; the thin film quality is enhanced: by in-situ introducing an inert gas (such as nitrogen), the oxidation of the thin film during annealing is inhibited, and at the same time, the oxygen vacancy concentration is regulated to improve the electrical properties of the thin film. Through the above improvements, the present invention solves the technical bottlenecks of complex process, uneven heating and high pollution risk in the traditional annealing process.

[0034] Additional advantages of the present invention will be given in the description which follows, and in part will be obvious from the description which follows, or may be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] To more clearly illustrate the embodiments of this application or the technical solutions in the prior art, the following briefly introduces the drawings required for the embodiments or the description of the prior art. Obviously, the drawings described below are only some of the embodiments described in this application. For those skilled in the art, other drawings can be derived from these drawings without inventive effort. In addition, the spacing or size between components is exaggerated to show the position of each component, and the schematic diagrams are for illustrative purposes only.

[0036] Figure 1 is a schematic diagram of an annealing assembly provided in an embodiment of the present invention;

[0037] Figure 2 This is an enlarged schematic diagram of the front heating plate provided by an embodiment of the present invention;

[0038] Figure 3 is a schematic diagram of the interior of a deposition chamber provided by an embodiment of the present invention;

[0039] Figure 4 is a schematic diagram of an annealing assembly provided by an embodiment of the present invention installed on a deposition chamber;

[0040] In the figure: 1. Electric heating wire; 2. Front heating plate; 3. Air outlet; 4. Rotating shaft; 5. Baffle; 6. Handle; 7. Fixing screw; 8. Gas valve; 9. Pulsed laser; 10. Target stage; 11. Target material; 12. Plasma; 13. Substrate; 14. Bottom support; 15. Growth gas tube; 16. Inlet valve; 17. Gas dispersion network. DETAILED DESCRIPTION

[0041] It should be noted that the following detailed description is illustrative and is intended to further illustrate the present invention. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as commonly understood by those of ordinary skill in the art to which the present invention belongs. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0042] like Figure 1 、 Figure 2 、 Figure 3 、 Figure 4 As shown, this embodiment proposes a (Al x Ga 1-x)2O3 thin film in-situ annealing device, comprising: a deposition chamber and an annealing assembly; a target table 10 and a base 14 are provided in the deposition chamber, and a set gap is provided between the target table 10 and the base 14; the annealing assembly comprises a rotating shaft 4, a front heating disk 2 and a baffle 5, the rotating shaft 4 is rotatably mounted on the deposition chamber, the front heating disk 2 and the baffle 5 are mounted at different circumferential angles on the inner end of the rotating shaft 4, and the front heating disk 2 and the baffle 5 are located between the target table 10 and the base 14, the rotating shaft 4 is a hollow tube, an air outlet 3 is provided on the front heating disk 2, and the hollow tube is connected to the air outlet 3 for introducing inert gas into the deposition chamber.

[0043] This in-situ annealing device eliminates the need to wait for the chamber to cool after film growth, remove the film, transfer it to the annealing furnace, and then re-evacuate, ventilate, and heat it. This greatly simplifies the annealing process and prevents unnecessary contamination during film transfer. Furthermore, inert gas is introduced through the hollow tube and the vent 3, further protecting the film and improving annealing quality.

[0044] like Figure 2 As shown, the eight radial air outlets on the front heating plate ensure uniform distribution of gas in the columnar heating area between the heating plate and the substrate holder. At the same time, a metal gas dispersion net 17 is added to all the air outlets. The function of the gas dispersion net 17 is to disperse the columnar airflow at the outlet, which helps the gas to diffuse in the columnar heating area and form inert gas protection as soon as possible. The second function is to appropriately reduce the gas flow rate by blocking the gas dispersion net 17, so as to avoid the problem of gas taking away heat in the initial stage of annealing temperature rise, thereby reducing the heating rate and causing uneven heating.

[0045] like Figure 1 As shown, an electric heating wire 1 is installed on the front heating plate 2 , and the electric heating wire 1 is coiled on the end surface of the front heating plate 2 where the air outlet 3 is provided.

[0046] The electric heating wire 1, made of an iron-chromium-aluminum alloy, is coiled around the front heating plate 2. The coiling path circumscribes the center of the plate, ensuring even heat distribution. This coiling pattern, combined with the position of the vents 3, prevents blockage of the gas path while minimizing temperature gradients across the heated surface of the film through radiant heat transfer. This significantly improves thermal uniformity during annealing and effectively reduces lattice stress caused by localized overheating or temperature differences.

[0047] like Figure 4 As shown, the annealing assembly further includes a handle 6, which is sleeved onto the rotating shaft 4 and secured with a fixing screw 7. A gas valve 8 for switching on and off inert gas is provided at the outer end of the rotating shaft 4. The deposition chamber is further provided with a growth gas pipe 15, the end of which is provided with an inlet valve 16.

[0048] A handle 6 is installed at the outer end of the rotating shaft 4, and the rotation angle of the rotating shaft 4 is locked by a fixing screw 7. The gas valve 8 at the end of the rotating shaft 4 is used to open and close the supply of inert gas. The operator can adjust the position of the heating plate through the external handle 6 and synchronously control the gas on and off. This design simplifies the annealing operation process, realizes the integrated control of heating and gas protection, and improves the process repeatability.

[0049] A target 11 is arranged on one side of the target stage 10 facing the bottom support 14, and a substrate 13 is arranged on one side of the bottom support 14 facing the target stage 10. The distance between the two is set to 4.7 - 10 cm. This distance range ensures that when the pulsed laser 9 ablates the target 11, the plasma plume 12 can effectively transmit to the surface of the substrate 13, while avoiding film defects caused by excessive particle energy. The corresponding positions of the substrate 13 and the target 11 provide an optimized deposition environment for film growth.

[0050] The diameter of the front heating plate 2 is 75 mm. When the front heating plate 2 is lowered, it is parallel to the bottom support 14 and the distance is 5 mm. This size design makes the heating area match the sample size, avoiding excessive heat diffusion to the surrounding cavity. The narrow 5 - mm distance forms a compact heating cavity, which can quickly reach the annealing temperature of the film through double - sided radiation heating, while reducing heat loss and improving energy utilization efficiency.

[0051] The relationship between the annealing temperature T, the film composition x, the film thickness d, and the inert gas flow rate Q is as follows:

[0052] T = T0 + ax + bln d + cQ (1);

[0053] Where T0 is the reference temperature, which is determined to be 700 °C through experiments. x ranges from 0.1 to 0.9. The film thickness d depends on different growth rates and growth durations according to different process parameters. The flow rate Q is in sccm, that is, standard cubic centimeters per minute. a, b, and c are coefficients.

[0054] The relationship between the annealing duration t, the gas flow rate Q, the temperature T, and the pressure P is as follows

[0055]

[0056] Where t is the annealing duration in seconds; A is the annealing factor, which is determined by the working density, molar mass of the gas, and the volume of the heating area. Here, it is taken as 0.022; R is the gas constant, taken as 8.314 Jmol -1 K -1 ; T and P are the annealing temperature and pressure in °C and Pa respectively, where T is determined by formula (1); Q is the gas flow rate in sccm.

[0057] In summary, the present invention offers a low-cost, simple improvement to the pulsed laser deposition heating system. Double-sided in-situ annealing, coupled with a distance of only 5 mm between the front heating plate 2 and the base 14, promotes uniform heating of the film and avoids thermal stress caused by temperature gradients. Inert gas is delivered through a gas pipeline within the front heating plate 2, further protecting the film while increasing oxygen vacancies and improving conductivity.

[0058] The annealing method based on the above annealing device includes the following steps:

[0059] After completing the thin film deposition in the pulse laser 9 deposition device, the sample is kept on the bottom support 14 of the deposition chamber;

[0060] The rotating shaft 4 is rotated to lower the front heating plate 2 to form a parallel structure with the bottom support 14. The front heating plate 2 is connected to the inert gas supply system through a hollow tube;

[0061] Activate the heating elements of the bottom support 14 and the front heating plate 2 to form a double-sided heating structure, set the heating temperature range and start the inert gas delivery to perform in-situ annealing on the film;

[0062] After maintaining the predetermined annealing time, the heating system and gas supply are turned off, and the annealed film is removed after the chamber cools naturally.

[0063] After the film deposition is completed, the front heating plate 2 is lowered to the vicinity of the bottom support 14 by rotating the shaft 4 to form a double-sided structure. The heating elements of the bottom support 14 and the front heating plate 2 are activated at the same time, the annealing temperature is set to 700-800°C, and an inert gas (such as nitrogen) is introduced through the hollow pipe of the shaft 4. Double-sided heating allows the film to be heated evenly in the thickness direction, eliminating the stress gradient caused by unilateral heating. Inert gas protection prevents film oxidation at high temperatures, and the annealing atmosphere is controlled by adjusting the gas flow rate to further reduce oxygen vacancy defects.

[0064] This method improves the heating system of the existing pulse laser 9 deposition equipment and adds a front heating disk 2 with a gas input function to achieve in-situ annealing of the film. This not only avoids the problem of possible contamination of the film when it is taken out for annealing, but also improves the uniformity of heating during film annealing. The introduction of inert gas can further protect the film, reduce film defects, and improve film quality.

[0065] The heating temperature range is 700-800°C, selected based on the film's lattice relaxation properties: below 700°C, atomic migration is insufficient, resulting in incomplete defect repair; above 800°C, the film may decompose or damage the substrate 13. Within this temperature range, aluminum and gallium ions can fully rearrange, releasing lattice distortion stress while maintaining the film's chemical stability.

[0066] The annealing duration is 30 - 60 min, and this duration balances the annealing efficiency and energy consumption: when it is shorter than 30 minutes, the defect elimination is insufficient; when it exceeds 60 minutes, it may cause excessive grain growth and affect the surface roughness of the thin film. Through experimental verification, this time window can reduce the film stress to an acceptable level and significantly improve the electrical properties (such as the carrier mobility is increased by 20% - 30%).

[0067] The inert gas is nitrogen. The chemical inertness of nitrogen can effectively isolate oxygen and prevent the thin film from oxidizing during high - temperature annealing. In addition, nitrogen has a relatively small molecular weight and a fast diffusion rate in the chamber, and can quickly form a uniform protective atmosphere. Compared with heavy inert gases such as argon, nitrogen has a lower cost and is easier to obtain, making it suitable for industrial applications.

[0068] Completing the thin - film deposition in a pulsed laser 9 deposition device includes:

[0069] Prepare a sapphire substrate 13;

[0070] Place the target 11 and the substrate 13 on the target stage 10 and the susceptor 14 respectively, fasten them with screws, and then put them into the deposition chamber. The distance between the target 11 and the substrate 13 is 4.7 - 10 cm;

[0071] Use a mechanical pump and a molecular pump to evacuate the chamber to 7×10 - 5 Pa, set the heating temperature of the substrate 13 to 600 - 680 °C, introduce high - purity oxygen, and control the oxygen pressure in the deposition chamber at 1 Pa;

[0072] After the environment in the chamber is stable, first perform pre - ablation to remove the contaminants on the surface of the target 11, and then use the pulsed laser 9 to ablate the target 11 for deposition. The laser wavelength is 248 nm, the energy of a single pulsed laser 9 is 150 - 450 mJ, the frequency is 3 - 10 Hz, and the number of pulses is 10800 - 36000.

[0073] Example 1

[0074] First, take out the target stage from the deposition cavity, place the target material and fasten it with screws, and then put the target stage back into the cavity. The atomic ratio of aluminum element to gallium element in the target material is 1:2.

[0075] Then, take out the susceptor from the deposition cavity, place the prepared sapphire substrate on the susceptor and press it tightly with a metal sheet, and then put the susceptor back into the cavity and adjust the distance between the target and the substrate to 5 cm.

[0076] Subsequently, close the chamber door, first use a mechanical pump to pump low vacuum, and then use a molecular pump to pump high vacuum until the background pressure of the chamber reaches 7×10 - 5 Pa.

[0077] After reaching the predetermined vacuum degree, turn on the substrate heating device, set the temperature to 600 °C, and the heating rate is 20 °C / min.

[0078] After heating to the set temperature, it is necessary to introduce the growth gas, which is high-purity oxygen in this embodiment. Open the intake valve to introduce oxygen, and use a molecular pump to control the pressure to keep the pressure in the chamber stable at 1 Pa.

[0079] After the pressure is stable, prepare for pre-sputtering to remove the contaminants on the target surface. First, control the rotating shaft to place the metal baffle between the target and the substrate to prevent contaminants from depositing on the substrate. Then, set the laser parameters as a single energy pulse of 300 mJ, a frequency of 5 Hz, a pulse number of 3000, and a sputtering time of 10 min to fully remove the contaminants.

[0080] Subsequently, open the metal baffle, set the laser parameters as a single pulse energy of 150 mJ, a frequency of 5 Hz, and a pulse number of 18000, and start deposition for 1 h.

[0081] After the deposition is completed, turn off the laser, start in-situ annealing. Control the rotating shaft to place the front heating plate between the substrate and the target, and fix the position with fixing screws. Turn on the heating power supply of the front heating plate, set the temperatures of the front heating plate and the bottom support heating wire to 800 °C respectively, the heating rate to 10 °C / min, the annealing time to 30 min, open the inert gas valve, and introduce inert gas, which is nitrogen in this embodiment.

[0082] After the annealing is completed, turn off the heating power supply, turn off the nitrogen, turn off the mechanical pump and the molecular pump, and wait for cooling to room temperature to take out the sample.

[0083] Comparative Example 1

[0084] First, take out the target stage from the deposition chamber, place the target and fasten it with screws, then put the target stage back into the chamber. The atomic ratio of aluminum element to gallium element in the target is 1:2.

[0085] Then, take out the bottom support from the deposition chamber, place the prepared sapphire substrate on the bottom support and press it tightly with a metal sheet, and then put the bottom support back into the chamber, and adjust the distance between the target and the substrate to 5 cm.

[0086] Subsequently, close the chamber hatch, first pump down to low vacuum with a mechanical pump, and then pump to high vacuum with a molecular pump, and finally make the background pressure of the chamber reach 7×10-5 Pa.

[0087] After reaching the predetermined vacuum degree, turn on the substrate heating device, set the temperature to 600 °C, and the heating rate to 20 °C / min.

[0088] After heating to the set temperature, it is necessary to introduce the growth gas, which is high-purity oxygen in this embodiment. Open the intake valve to introduce oxygen, and use a molecular pump to control the pressure to keep the pressure in the chamber stable at 1 Pa.

[0089] After the pressure is stabilized, prepare for pre-targeting to remove the contaminants on the surface of the target. First, control the rotating shaft to place the metal baffle between the target and the substrate to prevent the contaminants from depositing on the substrate. Then, set the laser parameters as a single energy pulse of 300 mJ, a frequency of 5 Hz, a pulse number of 3000, and a targeting time of 10 min to fully remove the contaminants.

[0090] Subsequently, open the metal baffle, set the laser parameters as a single pulse energy of 150 mJ, a frequency of 5 Hz, and a pulse number of 18000, and start deposition for 1 h. After the deposition is completed, turn off the heating, turn off the oxygen, turn off the mechanical pump and the molecular pump, and wait for it to cool to room temperature before taking out the sample.

[0091] Anneal using a tube furnace. First, rinse the film with deionized water and anhydrous ethanol in sequence to remove the contaminants such as dust on the surface, then dry it with a nitrogen gun. Put the sample into a quartz annealing box, push the annealing box to the heating area in the middle of the quartz tube of the annealing furnace, close the annealing furnace and plug the furnace plug. Use the mechanical pump to evacuate the quartz tube to a negative pressure, then open the oxygen valve to inflate the quartz tube. When the tube is filled with oxygen and the air pressure is equal to the atmospheric pressure, turn on the heating power supply and set the heating program: rise from room temperature to 800 °C at a heating rate of 10 °C / min, then hold at 800 °C for 30 min. After 30 min, stop the program and let it cool to room temperature with the furnace before taking out the sample.

[0092] It can be found from the above Example 1 and Comparative Example 1 that compared with the general annealing process of taking the film out of the cavity and then transferring it into the annealing furnace, in-situ annealing indeed greatly simplifies the operation process and can also prevent the sample from being contaminated by exposure to the air.

[0093] Although the specific implementation manners of the present invention are described above in conjunction with the drawings, it is not a limitation to the protection scope of the present invention. Those skilled in the art should understand that based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope of the present invention.

Claims

1. An (Al x Ga 1-x )2O3 thin film in-situ annealing device, characterized in that Comprising: A deposition chamber and an annealing assembly; A target stage and a bottom support are arranged in the deposition chamber, and a set gap is provided between the target stage and the bottom support; The annealing assembly includes a rotating shaft, a front heating disk and a baffle. The rotating shaft is rotatably installed on the deposition chamber. The front heating disk and the baffle are installed at different circumferential angles at the inner end of the rotating shaft, and the front heating disk and the baffle are located between the target stage and the bottom support. The rotating shaft is a hollow tube. The front heating disk is provided with air outlet holes, and a gas dispersion net is arranged in the air outlet holes. The hollow tube is communicated with the air outlet holes for introducing inert gas into the deposition chamber.

2. The (Al x Ga 1-x )2O3 thin film in-situ annealing device according to claim 1, characterized in that An electric heating wire is installed on the front heating disk, and the electric heating wire is wound on the end face of the front heating disk where the air outlet holes are provided.

3. The (Al x Ga 1-x )2O3 thin film in-situ annealing device according to claim 1, characterized in that The annealing assembly further includes a handle. The handle is sleeved on the rotating shaft and fixed with a fixing screw. A gas valve for switching on and off the inert gas is arranged at the outer end of the rotating shaft.

4. The in-situ annealing apparatus for the (Al x Ga 1-x )2O3 thin film according to claim 1, characterized in that A target material is arranged on one side of the target stage facing the bottom support, and a substrate is arranged on one side of the bottom support facing the target stage.

5. The (Al x Ga 1-x )2O3 thin film in-situ annealing device according to claim 1, characterized in that The diameter of the front heating disk is 75 mm. When the front heating disk is lowered, it is parallel to the bottom support and the distance therebetween is 5 mm.

6. An annealing method for an in-situ annealing apparatus of an (Al x Ga 1-x )2O3 thin film, characterized in that Including the following steps: After the film deposition is completed in the pulsed laser deposition equipment, keep the sample on the bottom support of the deposition chamber; Rotate the rotating shaft to lower the front heating disk until it forms a parallel structure with the bottom support. The front heating disk is communicated with the inert gas supply system through the hollow tube; Activate the heating elements of the bottom support and the front heating disk to form a double-sided heating structure, set the heating temperature range and start the inert gas delivery to perform in-situ annealing on the film; After maintaining the predetermined annealing duration, turn off the heating system and the gas supply. After the chamber cools naturally, take out the annealed film.

7. The annealing method according to claim 6, characterized in that The heating temperature range is 700 - 800 °C.

8. The annealing method according to claim 6, characterized in that, The annealing duration is 30 - 60 min.

9. The annealing method according to claim 6, characterized in that, The inert gas is nitrogen.

10. The annealing method according to claim 6, characterized in that, Completing the film deposition in the pulsed laser deposition equipment includes: Prepare a sapphire substrate; Place the target material and the substrate on the target stage and the bottom support respectively. After fastening with screws, put them into the deposition chamber. The distance between the target material and the substrate is 4.7 - 10 cm; Use a mechanical pump and a molecular pump to evacuate the chamber to 7×10-5 Pa, set the substrate heating temperature to 600 - 680 °C, introduce high-purity oxygen, and control the oxygen pressure in the deposition chamber to 1 Pa; After the environment in the chamber is stable, first perform pre-targeting to remove contaminants on the surface of the target material, and then use pulsed laser ablation of the target material for deposition. The laser wavelength is 248 nm, the energy of a single pulsed laser is 150 - 450 mJ, the frequency is 3 - 10 Hz, and the number of pulses is 10800 - 36000.

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