| 摘要 |
PROBLEM TO BE SOLVED: To provide a compound semiconductor substrate that controls cracks, crystallization defects, and warpage on a nitride semiconductor layer, and improves productivity. SOLUTION: The compound semiconductor substrate 1 has: a silicon single crystal substrate 10 with a crystal orientation as a surface (111); first buffer layers 20a and 20b formed on the silicon single crystal substrate 10 and made up of an Al<SB>x</SB>Ga<SB>1-x</SB>N single crystal (0<x≤1); a second buffer layer 30 formed on the first buffer layers 20a and 20b wherein a first single layer 30a made up of an Al<SB>y</SB>Ga<SB>1-y</SB>N single crystal (0≤y<0.1) with a thickness of≥250 nm and≤350 nm, and a second single layer 30b made up of an Al<SB>z</SB>Ga<SB>1-z</SB>N single crystal (0.9<z≤1) with a thickness of≥5 nm and≤20 nm, are alternately laminated in plural numbers; and a semiconductor element formation region 40 formed on the second buffer layer 30, which contains at least one nitride semiconductor single crystal layers. COPYRIGHT: (C)2011,JPO&INPIT
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