A method for preparing a high-concentration Sn-doped beta-phase gallium oxide single crystal thin film

Abstract

This invention discloses a method for preparing high-concentration Sn-doped β-phase gallium oxide single-crystal thin films. The method includes: target preparation A) weighing SnO2 powder and Ga2O3 powder; B) pouring the weighed powder into a mortar and adding an appropriate amount of anhydrous ethanol solution; C) placing the mortar on a constant-temperature heating stage and grinding until the anhydrous ethanol evaporates; D) placing the mixed powder into a mold and pressing it into shape; E) sintering the pressed target; F) using the sintered target to prepare the thin film. Thin film preparation: A) pretreating the sapphire substrate; B) setting the thin film growth parameters; C) setting the sample cooling parameters; D) obtaining the desired Sn-doped β-phase gallium oxide single-crystal thin film.

Description

Technical Field

[0001] This invention belongs to the field of preparation methods for single-crystal thin film materials, specifically relating to a method for preparing high-concentration Sn-doped β-phase gallium oxide single-crystal thin films. Background Technology

[0002] β-Ga₂O₃, as an ultrawide bandgap semiconductor material, holds significant promise for applications in high-power electronic devices and deep-ultraviolet optoelectronic devices due to its bandgap of 4.8–4.9 eV and theoretical breakdown electric field as high as 8 MV / cm. However, the low intrinsic carrier concentration of β-Ga₂O₃ limits its conductivity. To improve conductivity, tin (Sn) is widely used as an n-type dopant. However, studies have shown that Sn doping concentrations reaching 0.2 at% induce the formation of metastable ε-Ga₂O₃, resulting in a mixed crystal structure of ε and β phases in the film, affecting film quality and device performance. Therefore, developing a simple and inexpensive method for growing high-concentration Sn-doped β-Ga₂O₃ single-crystal films has significant research value and practical application implications. Summary of the Invention

[0003] Objective: In view of the above problems, this invention provides a method for preparing high-concentration Sn-doped β-phase gallium oxide single-crystal thin films. This method adopts a low-cost and simple operation approach and successfully prepares high-quality samples that meet expectations.

[0004] Technical Solution: To achieve the above-mentioned objectives, this invention proposes a method for preparing high-concentration Sn-doped β-phase gallium oxide single-crystal thin films, comprising the following steps:

[0005] Target preparation

[0006] A. Weigh the SnO2 powder and Ga2O3 powder according to the Sn doping concentration of 0.5 at%-10 at%;

[0007] B. Pour the powder weighed in step A into a mortar and add anhydrous ethanol to two-thirds of the mortar wall.

[0008] C. Place the mortar and pestle from step B on a constant temperature heating platform and grind at a preset temperature until the anhydrous ethanol has fully evaporated.

[0009] D. Add the powder obtained in step C to the binder and pour it into the mold of the hydraulic press. Press the target material into shape using the hydraulic press at a pressure of 40 MPa and hold the pressure for 5 minutes.

[0010] E. Place the target material obtained in step D into a tube furnace and sinter it in air at 1200 °C for 24 hours.

[0011] F. The target material obtained in step E is fed into a pulsed laser deposition (PLD) instrument, and then the thin film preparation begins;

[0012] Thin film preparation

[0013] A. Select a sapphire substrate and place it in a solution of acetone and anhydrous ethanol in a 1:1 ratio for ultrasonic cleaning; then heat it to 700°C at a heating rate of 10°C / min and hold it at that temperature for 1 hour to obtain an atomically smooth surface.

[0014] B. In the pulsed laser deposition system (PLD) used, the pulsed laser type for ablation of the target is a KrF excimer laser with a wavelength of 248 nm. Its laser energy is set to 450 mJ, its frequency to 5 Hz, the substrate growth temperature to 600 °C, and the oxygen partial pressure to 1 × 10⁻⁶. -3 mbar, nitrogen partial pressure is 9 × 10 -3 mbar; Thin film deposition process is performed under the above operating conditions;

[0015] C. After the thin film deposition process is completed, keep the gas pressure constant, set the cooling rate to 5 °C / min, cool down to 200 °C, and then turn off the heating device to cool to room temperature;

[0016] D. Remove the sample from the growth chamber to obtain the target sample.

[0017] Furthermore, in step B of the target preparation, the preset temperature is set to 80 ℃-120 ℃.

[0018] Furthermore, in the target preparation step D, a hydroforming method is used for molding.

[0019] Furthermore, in thin film preparation step B, a mixed growth atmosphere with an oxygen-nitrogen ratio of 1:9 is used.

[0020] Furthermore, in thin film preparation step D, β-phase gallium oxide single crystal thin films with Sn doping concentration of 0.5 at%-10 at% were prepared.

[0021] Beneficial effects: Compared with the prior art, the technical solution of the present invention has the following beneficial technical effects:

[0022] (1) The present invention achieves the growth of Sn-doped pure β-phase gallium oxide single crystal thin film by using oxygen-nitrogen mixed gas.

[0023] (2) In this invention, a pure β-phase gallium oxide single crystal thin film doped with Sn was prepared without the introduction of nitrogen.

[0024] (3) The present invention prepares a Sn-doped pure β-phase gallium oxide single crystal thin film with a low surface roughness.

[0025] (4) The technical route provided by the present invention only requires adjusting the atmosphere ratio on the basis of the original PLD growth process without changing other parameters. The process is simple, highly controllable, and easy to promote and apply. Attached Figure Description

[0026] Figure 1 This is a complete flowchart of the solid-state reaction method for sintering PLD targets. The role of adding a binder is to improve the plasticity and flowability of the powder, which facilitates the subsequent tableting process. It is a key step in obtaining a dense target material without macroscopic cracks.

[0027] Figure 2 The image shows the XRD pattern of this sample, which compares the diffraction peaks of the ε-phase, β+ε-phase, and β-phase gallium oxide films grown using the same target material at different oxygen-nitrogen ratios. It can be seen that the 2-Theta angles of 18.44°, 37.72°, and 58.43° correspond to the β-Ga₂O₃ (…). 01), ( 02), ( 03) The crystal planes belong to the same zone axis

[201] diffraction peaks, thus proving the growth of β-Ga2O3 single crystal thin films. Detailed Implementation

[0028] like Figure 1 As shown, this invention proposes a method for preparing high-concentration Sn-doped β-phase gallium oxide single-crystal thin films, which includes the following steps:

[0029] Target preparation

[0030] A. Weigh the SnO2 powder and Ga2O3 powder according to the Sn doping concentration of 0.5 at%-10 at%;

[0031] B. Pour the powder weighed in step A into a mortar and add anhydrous ethanol to two-thirds of the mortar wall.

[0032] C. Place the mortar and pestle from step B on a constant temperature heating platform and grind at a preset temperature until the anhydrous ethanol has fully evaporated.

[0033] D. Add the powder obtained in step C to the binder and pour it into the mold of the hydraulic press. Press the target material into shape using the hydraulic press at a pressure of 40 MPa and hold the pressure for 5 minutes.

[0034] E. Place the target material obtained in step D into a tube furnace and then sinter it in air at 1200°C for 24 hours.

[0035] F. The target material obtained in step E is fed into a pulsed laser deposition (PLD) instrument, and then the thin film preparation begins;

[0036] Thin film preparation

[0037] A. Select a sapphire substrate and place it in a solution of acetone and anhydrous ethanol in a 1:1 ratio for ultrasonic treatment to obtain a clean surface. Then heat it to 700 °C at a heating rate of 10 °C / min and hold it at that temperature for 1 hour to obtain an atomically smooth surface.

[0038] B. In the pulsed laser deposition system (PLD) used, the pulsed laser type for ablation of the target material is a KrF excimer laser with a wavelength of 248 nm. Its laser energy is set to 450 mJ, its frequency to 5 Hz, the substrate growth temperature to 600°C, and the oxygen partial pressure to 1 × 10⁻⁶. -3 mbar, nitrogen partial pressure is 9 × 10 -3 mbar; Thin film deposition process is performed under the above operating conditions;

[0039] C. After the thin film deposition process is completed, keep the gas pressure constant, set the cooling rate to 5°C / min, cool down to 200°C, and then turn off the heating device to cool to room temperature;

[0040] D. Remove the sample from the growth chamber to obtain the target sample.

[0041] Furthermore, in step B of the target preparation, the preset temperature is set to 80 ℃-120 ℃.

[0042] Furthermore, in the target preparation step D, a hydroforming method is used for molding.

[0043] Furthermore, in thin film preparation step B, a mixed growth atmosphere with an oxygen-nitrogen ratio of 1:9 is used.

[0044] Furthermore, in thin film preparation step D, β-phase gallium oxide single crystal thin films with Sn doping concentration of 0.5 at%-10 at% were prepared.

[0045] The target material prepared according to the above method was analyzed using wavelength dispersive spectroscopy (WDS), and the data obtained from three different locations of the sample are shown in Table 1 below. As can be seen from the data in Table 1, the elemental composition of the target material is Ga and Sn, with Ga comprising 16.295% atomic percentage, Sn 0.043% atomic percentage, and N 0.000% atomic percentage, indicating that nitrogen did not enter the thin film.

[0046] Table 1

[0047]

[0048] The above embodiments are preferred embodiments of the present invention, but the present invention is not limited to the above embodiments. Anyone can make changes or adjustments to the technical content and parameters mentioned in the present invention under the guidance of the present invention. Therefore, any additional changes or modifications made without departing from the essence and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1. A method for preparing a high-concentration Sn-doped β-phase gallium oxide single crystal thin film, characterized in that, The method includes the following steps: Target preparation A. Weigh the SnO2 powder and Ga2O3 powder according to the Sn doping concentration of 0.5 at%-10 at%; B. Pour the powder weighed in step A into a mortar and add anhydrous ethanol to two-thirds of the mortar wall. C. Place the mortar and pestle from step B on a constant temperature heating platform and grind at a preset temperature until the anhydrous ethanol has fully evaporated. D. Add the powder obtained in step C to the binder and pour it into the mold of the hydraulic press. Press the target material into shape using the hydraulic press at a pressure of 40 MPa and hold the pressure for 5 minutes. E. Place the target material obtained in step D into a tube furnace and sinter it in air at 1200 °C for 24 hours. F. The target material obtained in step E is fed into a pulsed laser deposition (PLD) instrument to begin thin film preparation; Thin film preparation; A. Select a sapphire substrate and place it in a solution of acetone and anhydrous ethanol in a 1:1 ratio for ultrasonic cleaning; then heat it to 700°C at a heating rate of 10°C / min and hold it at that temperature for 1 hour to obtain an atomically smooth surface. B、The pulse laser (PLD) instrument used is a KrF excimer laser, with a wavelength of 248 nm, a laser energy of 450 mJ, a frequency of 5 Hz, a substrate growth temperature of 600 °C, an oxygen partial pressure of 1×10 -3 mbar, and a nitrogen partial pressure of 9×10 -3 mbar, to perform the thin film deposition process under the above conditions. C. After the thin film deposition process is completed, keep the gas pressure constant, set the cooling rate to 5 °C / min, cool down to 200 °C, and then turn off the heating device to cool the film to room temperature. D. Remove the sample from the growth chamber to obtain the target sample.

2. The method for preparing a high-concentration Sn-doped β-phase gallium oxide single crystal thin film according to claim 1, characterized in that, In step B of the target preparation, the preset temperature is set to 80 ℃-120 ℃.

3. The method for preparing a high-concentration Sn-doped β-phase gallium oxide single crystal thin film according to claim 1, characterized in that, In step D of the target material preparation, the target material is formed using a hydroforming method.

4. The method for preparing a high-concentration Sn-doped β-phase gallium oxide single crystal thin film according to claim 1, characterized in that, In thin film preparation step B, a mixed growth atmosphere with an oxygen-nitrogen ratio of 1:9 is used.

5. The method for preparing a high-concentration Sn-doped β-phase gallium oxide single crystal thin film according to claim 1, characterized in that, In thin film preparation step D, β-phase gallium oxide single crystal thin films with Sn doping concentration of 0.5 at%-10 at% were prepared.

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