A method for improving the quality of a β-gallium oxide epitaxial layer by inserting an aluminum-gallium oxide buffer layer

Abstract

The application relates to the field of semiconductor material film epitaxy, and particularly discloses a method for improving the quality of a beta gallium oxide epitaxial layer by inserting an aluminum gallium oxygen buffer layer, which comprises the following steps: immersing sapphire substrates in acetone and anhydrous ethanol respectively for 10 minutes, performing preliminary cleaning, then placing the sapphire substrates in an ultrasonic cleaning machine, cleaning the sapphire substrates at 30 DEG C for 20 minutes, taking out the sapphire substrates, rinsing the sapphire substrates with deionized water and drying the sapphire substrates with a nitrogen gun; the aluminum gallium oxygen buffer layer is grown on the sapphire substrates by adopting a magnetron sputtering method, and a gallium oxide epitaxial layer is grown on the aluminum gallium oxygen buffer layer by adopting a hydride vapor phase epitaxy (HVPE) method; the gallium oxide epitaxial layer obtained by inserting the aluminum gallium oxygen buffer layer is characterized, and the experimental results show that, under the growth condition of the aluminum gallium oxygen buffer layer, the stress value of the gallium oxide epitaxial layer is smaller, and with the decrease of the tensile stress in the gallium oxide epitaxial layer, the crystal quality of the sample is significantly improved.

Description

Technical Field

[0001] This invention relates to a method for improving gallium oxide epitaxial layers by inserting an aluminum gallium oxide buffer layer, belonging to the field of thin film epitaxy of semiconductor materials. Background Technology

[0002] Gallium oxide (GaO), as a novel ultra-wide bandgap semiconductor material, boasts a bandgap of 4.8 electron volts (eV), significantly wider than other compound semiconductors such as silicon carbide (SiC) and gallium nitride (GaN). This wide bandgap characteristic gives GaO enormous application potential in power switches and radio frequency (RF) electronic devices. Furthermore, its higher breakdown field strength and low-cost melt fabrication capabilities make it an ideal material for next-generation high-power electronics, RF, and solar-blind ultraviolet photodetectors. The development of GaO materials is of great significance to the entire semiconductor industry.

[0003] The high-quality mass production of gallium oxide is urgently needed. Hydride vapor phase epitaxy (HVPE) has become one of the important methods for realizing the mass production of gallium oxide epitaxial films due to its advantages of efficient manufacturing of high-quality epitaxial layers, large-area uniform growth of epitaxial layers, and reduced manufacturing costs.

[0004] The crystal quality of gallium oxide epitaxial layers is also crucial to device performance. The stress state of the epitaxial layer is one of the important factors affecting crystal quality. This invention proposes a solution to address the above problem: by inserting an aluminum gallium oxide buffer layer to reduce the tensile stress of the gallium oxide epitaxial layer, thereby improving the crystal quality of the gallium oxide epitaxial layer. Summary of the Invention

[0005] The purpose of this invention is to provide a method for improving the quality of β-phase gallium oxide epitaxial layers by inserting an aluminum gallium oxide buffer layer.

[0006] The technical solution of the present invention is as follows: A method for improving gallium oxide epitaxial layers by inserting an aluminum gallium oxide buffer layer includes the following steps: The substrate was initially cleaned by immersing it in acetone and anhydrous ethanol for 10 minutes each. Then, it was placed in an ultrasonic cleaner and cleaned at 30°C for 20 minutes. After removal, it was rinsed with deionized water and dried with a nitrogen gun. The cleaned substrate is fixed on the sample stage, leaving a gap during fixing, and the aluminum gallium oxide target is placed on the target position of the magnetron sputtering equipment. Close the chamber door of the coating equipment and evacuate the chamber for 10 minutes; Before introducing the working gas, turn on the sputtering power supply and set the pre-sputtering power to 150-280W to pre-sputter the aluminum gallium oxide target for 5-10 minutes. Argon and oxygen are introduced into the chamber. The argon flow rate is set to 30-50 sccm, the oxygen flow rate is set to 5-15 sccm, the sputtering power is set to 300-400W, and the bias voltage is set to -100V. Sputtering is then started. After the substrate is placed into the chamber, the growth temperature is set. Once the heating stage reaches 200-400℃, it is maintained for 15 minutes. A glow discharge phenomenon was observed at the start of film deposition, and the growth temperature was kept constant during the deposition process. After sputtering is complete, turn off the sputtering power supply and gas valve, and wait for the temperature to drop to room temperature before taking out sample 1; After blowing the surface of sample 1 with a nitrogen gun, fix it on the graphite tray and send it to the growth temperature zone of the HVPE equipment. Close the equipment and start the process, and open the mechanical pump and main extraction valve. Close all pipelines and evacuate the chamber for 15 minutes; Open all pipelines and evacuate the pipelines for 5 minutes; Turn on the heating system of the HVPE equipment, set the source zone temperature to 800~900℃ and the growth zone temperature to 900~1000℃, raise the temperature for 1-2 hours, and continuously introduce nitrogen gas; Increase the nitrogen flow rate to 1500~2000 sccm, set the reaction pressure to 40 kPa, and start the rotation at a speed of 1 r / min. First, introduce oxygen at a flow rate of 300-500 sccm, then introduce hydrogen chloride at a flow rate of 10-20 sccm. Adjust the nitrogen flow rate in gas line 2 to 1000-1500 sccm, and maintain the total nitrogen flow rate at 1500-2000 sccm. Grow for 1 hour using the parameters set above; Turn off the oxygen supply and the hydrogen chloride supply, and adjust the reaction pressure to 0. The reaction chamber was purged with nitrogen at a flow rate of 1000 sccm for 1 hour. Close all air passages, stop rotation, turn on the HVPE cooling system, and end the process when the temperature drops to 50°C. Open the main extraction valve and remove sample 2; Detailed Implementation

[0007] The technical solution of the present invention will be further described below with reference to specific embodiments.

[0008] Example 1: This embodiment provides a method for improving the quality of β-phase gallium oxide epitaxial layers by inserting an aluminum gallium oxide buffer layer, the steps of which include: Using a 4-inch sapphire single-crystal wafer as a substrate, the sapphire substrate was immersed in acetone and anhydrous ethanol for 10 minutes each for preliminary cleaning. Then, it was placed in an ultrasonic cleaner and cleaned at 30°C for 20 minutes. After removal, it was rinsed with deionized water and dried with a nitrogen gun. The cleaned substrate is fixed on the sample stage, leaving a gap during fixing, and the aluminum gallium oxide target is placed on the target position of the magnetron sputtering equipment. Close the chamber door of the coating equipment and evacuate the chamber for 10 minutes; Before introducing the working gas, turn on the sputtering power supply, set the pre-sputtering power to 210W, and pre-sputter the aluminum gallium oxide target for 10 minutes. Argon and oxygen are introduced into the chamber. The argon flow rate is set to 40 sccm and the oxygen flow rate to 10 sccm. The sputtering power is set to 350W and the bias voltage to -100V. Sputtering is then started. After the substrate is placed into the chamber, the growth temperature is set. Once the heating stage reaches 300°C, it is maintained for 15 minutes. The system is set to begin depositing a thin film upon observation of glow discharge, and the growth temperature is kept constant during the deposition process. After sputtering is complete, turn off the sputtering power supply and gas valve, and wait for the temperature to drop to room temperature before taking out sample 1; After blowing the surface of sample 1 with a nitrogen gun, fix it on the graphite tray and send it to the growth temperature zone of the HVPE equipment. Close the equipment and start the process, and open the mechanical pump and main extraction valve. Shut down all pipelines and evacuate the chamber for 15 minutes. Open all pipelines and evacuate the pipelines for 5 minutes; Turn on the heating system of the HVPE equipment, set the source zone temperature to 900℃ and the growth zone temperature to 1000℃, heat for 1 hour, and continuously introduce nitrogen gas. Increase the nitrogen flow rate to 1700 sccm, set the reaction pressure to 40 kPa, and start the rotation at a speed of 1 r / min. First, introduce oxygen at a flow rate of 400 ccm, then introduce hydrogen chloride at a flow rate of 15 sccm, adjust the nitrogen flow rate in gas line 2 to 1300 ccm, and keep the total nitrogen flow rate at 1700 sccm. Grow for 1 hour using the parameters set above; Turn off the oxygen supply and the hydrogen chloride supply, and adjust the reaction pressure to 0. The reaction chamber was purged with nitrogen at a flow rate of 1000 sccm for 1 hour. Close all air passages, stop rotation, turn on the HVPE cooling system, and end the process when the temperature drops to 50°C. Open the main extraction valve to obtain sample 2, which is a β-phase gallium oxide epitaxial wafer with sapphire as substrate, aluminum gallium oxide as buffer layer, and gallium oxide epitaxial layer; The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.

Claims

1. It should be noted that any simple modifications or alterations without departing from the core of this invention fall within the protection scope of this invention.

2. Other equivalent substitutions that can be made by those skilled in the art without inventive effort all fall within the protection scope of this invention.