GARIUM NITRIDE SEMICONDUCTOR DEVICE

摘要

PROBLEM TO BE SOLVED: To provide a GaN semiconductor device in an HEMT structure, with which on-resistance in operation is low and large current operation is enabled. SOLUTION: A GaN semiconductor device A is composed of GaN semiconductor materials as a whole. The layer structure is formed of a lower layer 3 composed of a first undoped material, and an upper layer 4 composed of a second undoped material having band gap energy greater than that of the first undoped material on a substrate 1. In the device A, a gate electrode G, a source electrode S and a drain electrode D are formed on the surface of the upper layer 4. The thickness of the upper layer 4 in a forming region 4A of the source electrode S and the drain electrode D is reduced rather than thickness in another region 4B.