US 12,446,281 B2
Nitride semiconductor substrate manufacturing method, and laminated structure
Takehiro Yoshida, Hitachi (JP)
Assigned to SUMITOMO CHEMICAL COMPANY, LIMITED, Tokyo (JP)
Appl. No. 17/292,192
Filed by SUMITOMO CHEMICAL COMPANY, LIMITED, Tokyo (JP)
PCT Filed Nov. 8, 2019, PCT No. PCT/JP2019/043879
§ 371(c)(1), (2) Date May 7, 2021,
PCT Pub. No. WO2020/096045, PCT Pub. Date May 14, 2020.
Claims priority of application No. 2018-210536 (JP), filed on Nov. 8, 2018.
Prior Publication US 2021/0391427 A1, Dec. 16, 2021
Int. Cl. C30B 15/20 (2006.01); C30B 29/38 (2006.01); H01L 21/02 (2006.01); H01L 21/304 (2006.01); H10D 62/85 (2025.01)
CPC H10D 62/8503 (2025.01) [C30B 29/38 (2013.01); H01L 21/022 (2013.01); H01L 21/02263 (2013.01); H01L 21/02293 (2013.01); H01L 21/02389 (2013.01); H01L 21/304 (2013.01)] 11 Claims
OG exemplary drawing
 
1. A method for manufacturing a nitride semiconductor substrate, the method comprising:
a step of preparing a base substrate that is a first single crystal of a first group III nitride semiconductor and in which a low index crystal plane closest to a main surface is a (0001) plane;
an etching step of etching the main surface of the base substrate to roughen the main surface and to generate a plurality of first recessed portions in the main surface;
a first step of vapor phase growing a first layer by epitaxially growing a second single crystal of a second group III nitride semiconductor on the main surface of the base substrate, a plurality of second recessed portions formed by inclined interfaces other than the (0001) plane being generated in a surface of the second single crystal due to the roughened main surface of the base substrate, and at least some of the plurality of second recessed portions being gradually expanded toward an upper side of the main surface of the base substrate by adjusting a crystal growth condition and a number of the second recessed portions in the second single crystal being reduced to be less than a number of the first recessed portions in the base substrate by expanding the second recessed portions, the first layer including a first surface from which the (0001) plane has disappeared and that is constituted only by the inclined interfaces;
a second step of vapor phase growing a second layer including a mirror second surface by epitaxially growing a third single crystal of a third group III nitride semiconductor on the first layer so as to make the inclined interfaces disappear, and
a step of slicing at least one substrate as the nitride semiconductor substrate from the second layer after the second step,
wherein the base substrate, the first layer and the second layer do not include an inversion domain.