NITRIDE SEMICONDUCTOR WAFER, NITRIDE SEMICONDUCTOR DEVICE, AND METHOD FOR MANUFACTURING NITRIDE SEMICONDUCTOR WAFER

摘要

According to one embodiment, a nitride semiconductor wafer (110, 111, 112, 113, 114) includes: a silicon substrate (40); a buffer section (50) provided on the silicon substrate (40); and a functional layer (10s) provided on the buffer section (50) and contains nitride semiconductor. The buffer section (50) includes first to n-th buffer layers (BF1, BF2, BF3, BF4, BF5, BF6, BFn) (n being an integer of 4 or more) containing nitride semiconductor. An i-th buffer layer (BFi) (i being an integer of 1 or more and less than n) of the first to n-th buffer layers (BF1, BF2, BF3, BF4, BF5, BF6, BFn) has a lattice length Wi in a first direction parallel to a major surface (BF1a) of the first buffer layer (BF1). An (i+1)-th buffer layer (BF(i+1)) provided on the i-th buffer layer (BFi) has a lattice length W(i+1) in the first direction. In the first to n-th buffer layers (BF1, BF2, BF3, BF4, BF5, BF6, BFn) the i-th buffer layer (BFi) and the (i+1)-th buffer layer (BF(i+1)) satisfy relation of (W(i+1)-Wi)/Wi ‰¤ 0.008.