SEMICONDUCTOR SUBSTRATE, SEMICONDUCTOR DEVICE, AND METHOD FOR MANUFACTURING SEMICONDUCTOR SUBSTRATE

摘要

Disclosed is a semiconductor substrate which is provided with a base substrate, a first crystal layer formed on the base substrate, a second crystal layer covering the first crystal layer, and a third crystal layer formed in contact with the second crystal layer. The first crystal layer has a first crystal plane, which has a plane orientation equal to that of a base substrate surface in contact with the first crystal layer, and a second crystal plane, which has a plane orientation different from that of the first crystal plane, the second crystal layer has a third crystal plane, which has a plane orientation equal to that of the first crystal plane, and a fourth crystal plane, which has a plane orientation equal to that of the second crystal plane, and the third crystal layer is in contact with at least respective parts of the third crystal plane and the fourth crystal plane. The ratio of the thickness of the second crystal layer in a region in contact with the second crystal plane to the thickness of the second crystal layer in a region in contact with the first crystal plane is larger than the ratio of the thickness of the third crystal layer in a region in contact with the fourth crystal plane to the thickness of the third crystal layer in a region in contact with the third crystal plane.