NITRIDE SEMICONDUCTOR DEVICE

摘要

A nitride semiconductor device comprises a first nitride semiconductor layer (3), a second nitride semiconductor layer (4), a third nitride semiconductor layer (5) and a fourth nitride semiconductor layer (6) all of which are formed in this order on a substrate (1). A channel is formed, in which a carrier is accumulated in the third nitride semiconductor layer (5) in the vicinity of the interface between the third nitride semiconductor layer (5) and the fourth nitride semiconductor layer (6). The second nitride semiconductor layer (4) has a larger band gap than that of the third nitride semiconductor layer (5). The first nitride semiconductor layer (3) has a band gap that is equal to or larger than that of the second nitride semiconductor layer (4), and carbon is doped into the first nitride semiconductor layer (3) at a higher concentration than that in the second nitride semiconductor layer (4).