Patent ID: 11873578
Assignee: SUMITOMO CHEMICAL COMPANY LIMITED
Field: Semiconductors (Electrical engineering)
Classification: CPC C  H | IPC C  H

Claim 0:
1. A method for manufacturing a nitride semiconductor substrate by using a vapor phase growth method, comprising:
a step of preparing a base substrate that is constituted by a material different from a single crystal of a group III nitride semiconductor;
a step of growing a base layer that has a mirror-finished base surface and in which a low index crystal plane closest to the base surface is a (0001) plane, by epitaxially growing a single crystal of a group III nitride semiconductor on the upper side of the base substrate;
a first step of growing a first layer by epitaxially growing a single crystal of a group III nitride semiconductor directly on the base surface of the base layer, the single crystal of the group III nitride semiconductor having a top surface at which a (0001) plane is exposed, a plurality of recessed portions formed by inclined interfaces other than the (0001) plane being generated in the top surface, the inclined interfaces being gradually expanded toward an upper side of the base surface of the base layer to make the (0001) plane disappear from the top surface, and a surface of the first layer being constituted only by the inclined interfaces; and
a second step of growing a second layer that has a mirror-finished surface by epitaxially growing a single crystal of a group III nitride semiconductor on the first layer so as to make the inclined interfaces disappear,
wherein, in the first step, the plurality of recessed portions are generated in the top surface of the single crystal after the single crystal is grown so as to have a predetermined thickness with the (0001) plane serving as a growth surface.