| 摘要 |
PROBLEM TO BE SOLVED: To provide a semiconductor substrate whose crystallinity and flatness are sufficient, whose yield is high and whose high breakdown strength is realized. SOLUTION: The semiconductor substrate is constituted of a first Si layer 9-1 composed mainly of Si, an SiGe layer 9-4, and a second Si layer 9-3 which is interposed and installed between the Si layer 9-1 and the SiGe layer 9-4 and which covers a part as a surface layer part 9-2 on the Si layer 9-1 and containing impurities. The Si layer 9-3 prevents deterioration of the flatness of the surface layer as the SiGe layer 9-4 in such a way that the SiGe mixed crystal structure of the SiGe layer 9-4 is moved away from the impurity layer 9-2 on the Si layer 9-1. When the deterioration of the flatness is prevented, the breakdown strength of the semiconductor substrate is enhanced when used in an electronic device, and the yield of the semiconductor substrate is enhanced.
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