| 主权项 |
1. A nitride semiconductor device, comprising:
an electron transport layer made of a nitride semiconductor; an electron supply layer layered on the electron transport layer, the electron supply layer being made of a nitride semiconductor including Al and having an Al composition different from that of the electron transport layer; a source electrode and a drain electrode disposed on the electron supply layer with a gap therebetween; a gate insulating film covering a surface of the electron supply layer between the source and the drain electrode; a mpassivation film covering a surface of the gate insulating film and having an opening between the source electrode and the drain electrode, the opening being at a distance from the source electrode and the drain electrode; and a gate electrode disposed in the opening in the passivation film and in contact with the gate insulating film, the gate electrode having a main gate body facing the electron supply layer through the gate insulating film, wherein the gate insulating film is a multilayer gate insulating film including a first insulating layer in contact with the electron supply layer, and a second insulating layer layered onto the first insulating layer at least under a lowest bottom surface of the main gate body of the gate electrode, wherein a first portion of the first insulating layer is disposed directly under, and in contact with, a first bottom surface of the source electrode and a second portion of the insulating layer is disposed directly under and in contact with a first bottom surface of the drain electrode and a second bottom surface of the source electrode and a second bottom surface of the drain electrode are in contact with the electron supply layer, respectively, and wherein portions of the second insulating layer are disposed on portions of top surfaces of the source electrode and the drain electrode, respectively. |
