Nitride semiconductor device, nitride semiconductor wafer, and method for manufacturing nitride semiconductor layer

摘要

According to one embodiment, a nitride semiconductor device (110, 111, 120) includes: a stacked foundation layer (50), and a functional layer (10s). The stacked foundation layer (50) is formed on an AIN buffer layer (55) formed on a silicon substrate (40). The stacked foundation layer (50) includes AIN foundation layers (52) and GaN foundation layers (51) being alternately stacked. The functional layer (10s) includes a low-concentration part (10l), and a high-concentration part (10h) provided on the low-concentration part (10l). A substrate-side GaN foundation layer (51 s) closest to the silicon substrate (40) among the plurality of GaN foundation layers (51) includes first portion (51a) and second portion (51b), and a third portion (51c) provided between the first and second portions (51a, 51b). The third portion (51c) has a Si concentration not less than 5 X 10 18 cm -3 and has a thickness smaller than a sum of those of the first and second portions (51a, 51b).