| 摘要 |
PROBLEM TO BE SOLVED: To inhibit warpage, and achieve reduction in leakage current and improvement in a particle-induced pit.SOLUTION: A nitride semiconductor epitaxial wafer comprises: an Si substrate (1); a ground layer (2) which is formed on the Si substrate (1) and composed of AlN; an Al compositional gradient layer (7) which is formed on the ground layer (2) and in which a plurality of layers each composed of a composition represented as AlGaN(0<x<1) where an Al composition gradually decreases from bottom up when assuming that the Si substrate side is the bottom are laminated; and nitride semiconductors (8, 9) formed on the Al compositional gradient layer (7). At least any one interlayer out of a plurality of interlayers in the Al compositional gradient layer (7), any of local low Al compositions AlGaN, GaN and AlN is formed, and the above described local low Al composition AlGaN has an Al composition lower than each of Al compositions of both AlGaN layers located immediately below and immediately above the local low Al composition AlGaN in the Al compositional gradient layer (7).SELECTED DRAWING: Figure 1 |
