SEMICONDUCTOR WAFER AND SEMICONDUCTOR DEVICE

摘要

A semiconductor wafer is provided with a substrate and a group III nitride semiconductor layer provided on the substrate with a multilayer buffer layer interposed therebetween. The multilayer buffer layer includes at least a first buffer layer and a second buffer layer. The first buffer layer is in contact with the group III nitride semiconductor layer. The second buffer layer is in contact with the first buffer layer, and has a different composition from the first buffer layer. The average lattice constant of the multilayer buffer layer is lower than that of the group III nitride semiconductor layer, and the interface lattice distortion of the group III nitride semiconductor layer at the interface between the group III nitride semiconductor layer and the first buffer layer is lower than the interface lattice distortion of the first buffer layer at the interface between the first buffer layer and the second buffer layer.