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CN-121976293-A - Gallium oxide epitaxial growth method

CN121976293ACN 121976293 ACN121976293 ACN 121976293ACN-121976293-A

Abstract

The invention provides a gallium oxide epitaxial growth method, and belongs to the field of crystal preparation. The invention carries out beveling processing on the (001) surface of a beta-Ga 2 O 3 substrate to obtain the bevelled (001) substrate, wherein the beveling processing direction is the [ -100] direction, and the angle is 0.1-6 degrees. The invention provides a substrate surface structure which is easy to generate twin crystal defects and is formed by beveling a beta-Ga 2 O 3 (001) surface substrate towards the [ -100] direction so as to expose a specific substrate surface step surface (a step structure taking a (-201) surface as a step side), the substrate surface structure which is easy to generate twin crystal defects is avoided, the step structure which is formed by beveling towards the [ -100] direction and other possible directions and takes the (100) surface as the step side is avoided, spontaneous formation of twin crystal defects caused by the structure is prevented, the substrate surface structure can be applied to epitaxial growth, high-quality epitaxial thin films are obtained, and the crystal quality in the beta-Ga 2 O 3 epitaxial process is improved.

Inventors

  • XIA NING
  • LI CHENG

Assignees

  • 杭州镓仁半导体有限公司

Dates

Publication Date
20260505
Application Date
20241028

Claims (10)

  1. 1. A method of epitaxial growth of gallium oxide comprising the steps of: carrying out chamfering processing on the (001) surface of the beta-Ga 2 O 3 substrate to obtain a chamfered (001) substrate, wherein the chamfering processing direction is the [ -100] direction, and the angle is 0.1-6 degrees; gallium oxide epitaxial growth is performed on the beveled (001) substrate surface.
  2. 2. The method of claim 1, wherein the angle of the chamfer process is 1 ° to 5 °.
  3. 3. The method of claim 2, wherein the angle of the chamfer process is 2 ° to 4 °.
  4. 4. The method of claim 1, further comprising thermally treating the beveled (001) substrate prior to epitaxial growth of the gallium oxide.
  5. 5. The method according to claim 4, wherein the atmosphere of the heat treatment is an oxygen-nitrogen mixed gas, the volume percentage of oxygen in the oxygen-nitrogen mixed gas is 0% -100% and is not 0%, and is not 100%, the temperature of the heat treatment is 800-1500 ℃ and the time is 0.5-48 h.
  6. 6. The method of claim 5, wherein the heat treatment is performed at a temperature of 1000-1200 ℃ for a time of 5-24 hours.
  7. 7. The method according to claim 1, wherein the gallium oxide epitaxial growth uses a metal organic chemical vapor deposition method, the metal organic chemical vapor deposition method has a temperature of 400-1200 ℃, a pressure of 5-100 mbar, a trimethylgallium flow rate of 10-150 sccm, an oxygen flow rate of 1000-10000 sccm, and a time of 0.5-48 h.
  8. 8. The method according to claim 1, wherein the gallium oxide epitaxial growth uses a halide vapor phase epitaxy method, the temperature of the halide vapor phase epitaxy method is 400-1200 ℃, the growth pressure is 10-500 torr, the hcl flow is 10-150 sccm, the oxygen flow is 100-5000 sccm, the carrier gas flow is 100-5000 sccm, and the time is 0.5-48 h.
  9. 9. The method according to claim 1, wherein the gallium oxide epitaxial growth uses a metal organic vapor phase epitaxy method, the metal organic vapor phase epitaxy method has a temperature of 400-1200 ℃, a pressure of 5-100 mbar, a trimethylgallium flow of 5-150 sccm, an oxygen flow of 100-10000 sccm, and a time of 0.5-48 h.
  10. 10. The method according to claim 1, wherein the gallium oxide epitaxial growth uses a molecular beam epitaxy method, the temperature of the molecular beam epitaxy method is 400-1200 ℃, the equivalent pressure of Ga beam is 1 x 10 -7 ～1×10 -6 mbar, the oxygen plasma flow is 0.5-4 sccm, the power of oxygen plasma is 300W, and the time is 0.5-48 h.

Description

Gallium oxide epitaxial growth method Technical Field The invention relates to the technical field of crystal preparation, in particular to a gallium oxide epitaxial growth method. Background Gallium oxide is an oxide semiconductor with an ultra-wide band gap of 4.7-4.9 eV, has the remarkable advantages of high breakdown field strength (about 8 MeV/cm), stable physical and chemical properties and the like, has wide application prospect in the aspects of power devices and solar blind ultraviolet detectors, and is the most likely material for realizing commercial application in the ultra-wide band gap semiconductor. High quality single crystal growth and substrate development are key bases for achieving high performance gallium oxide device fabrication. To produce high performance beta-Ga 2O3 devices, an epitaxial thin film layer needs to be prepared on the beta-Ga 2O3 substrate. Currently, the β -Ga 2O3 epitaxy method includes Metal Organic Chemical Vapor Deposition (MOCVD), halide Vapor Phase Epitaxy (HVPE), metal Organic Vapor Phase Epitaxy (MOVPE), molecular Beam Epitaxy (MBE), and the like. Because of the lamellar distributed atomic structure in the β -Ga 2O3 crystal, a β -Ga 2O3 single crystal substrate with the (001) plane may expose a distinct step structure when beveled in a particular direction. The step structure is favorable for forming good step flow growth in the epitaxial process, and the epitaxial crystal quality is improved. However, due to the low symmetry of β -Ga 2O3, the (001) plane substrate is beveled along a series of directions, for example, the direction of [100], and then the exposed step surface induces a specific twin defect to spontaneously form in epitaxy, which is difficult to avoid by technical means, so that the beveled direction of the β -Ga 2O3 (001) plane substrate needs to be controlled to avoid the step structure resulting in defect generation, so as to improve the crystal quality in the epitaxy process. At present, the related proposal of the prior art is that a continuous chamfer angle is manufactured on the upper surface of a (001) crystal face gallium oxide substrate layer, an epitaxial film is grown on the (001) crystal face gallium oxide substrate layer with the continuous chamfer angle, and the (001) crystal face substrate is inclined at an angle of more than or equal to 0.5 degrees towards the [100] crystal face direction, the [010] crystal face direction or both directions, so as to achieve the purpose of step flow growth, and the setting of the chamfer angle enables the (001) crystal face gallium oxide substrate to obtain low-roughness and high-quality homoepitaxy. However, due to the low symmetry of the β -Ga 2O3 crystal, the (001) plane substrate is inclined towards the [100] crystal plane direction or other part of specific crystal plane directions to form an atomic level step exposed on the surface of the substrate, which is easy to be a cause of spontaneously formed twin crystal defects, so that the crystal quality is greatly reduced. Disclosure of Invention In view of the above, an object of the present invention is to provide a method for epitaxial growth of gallium oxide. The method of the invention avoids the step structure which takes the (100) surface as the step side surface and is caused by the inclined cutting towards the [100] direction and other possible directions, prevents the spontaneous formation of twin crystal defects caused by the structure, can be applied to epitaxial growth, and obtains high-quality epitaxial films. In order to achieve the above object, the present invention provides the following technical solutions: the invention provides a gallium oxide epitaxial growth method, which comprises the following steps: carrying out chamfering processing on the (001) surface of the beta-Ga 2O3 substrate to obtain a chamfered (001) substrate, wherein the chamfering processing direction is the [ -100] direction, and the angle is 0.1-6 degrees; gallium oxide epitaxial growth is performed on the beveled (001) substrate surface. Preferably, the angle of the beveling process is 1-5 °. Preferably, the angle of the beveling process is 2-4 °. Preferably, the gallium oxide epitaxial growth is preceded by a heat treatment of the beveled (001) substrate. Preferably, the atmosphere of the heat treatment is an oxygen-nitrogen mixed gas, the volume percentage of oxygen in the oxygen-nitrogen mixed gas is 0% -100% and is not 0% or 100%, the temperature of the heat treatment is 800-1500 ℃, and the time is 0.5-48 h. Preferably, the temperature of the heat treatment is 1000-1200 ℃ and the time is 5-24 hours. Preferably, the gallium oxide epitaxial growth uses a metal organic chemical vapor deposition method, wherein the temperature of the metal organic chemical vapor deposition method is 400-1200 ℃, the pressure is 5-100 mbar, the flow rate of trimethylgallium is 10-150 sccm, the flow rate of oxygen is 1000-10000 sccm, and the time is 0.5-48 h. Preferably, t