III NITRIDE SEMICONDUCTOR MULTILAYER SUBSTRATE AND III NITRIDE SEMICONDUCTOR FIELD EFFECT TRANSISTOR

摘要

A III nitride semiconductor multilayer substrate (100) is provided with: a channel layer (5), i.e., a III nitride semiconductor; and a barrier layer (6), i.e., a III nitride semiconductor, which is formed on the channel layer (5), and which forms a hetero interface with the channel layer (5). The barrier layer (6, 206) has a Cu concentration of 1.0×1010 (number of atoms/cm2) or less in a region having a depth of 10 nm or less from the surface.