INSULATING GATE FIELD EFFECT TRANSISTOR

摘要

PROBLEM TO BE SOLVED: To prevent deterioration of a surface profile when AlN films of a crystal thin film having a lattice constant/thermal expansion coefficient different from that of a base crystal is used as a gate insulating film in a GaN-HEMT of an insulating gate structure. SOLUTION: The GaN-HEMT of an insulating gate structure is provided with a crystal thin film gate insulating film (34) on a hetero-structure of a barrier layer/electron supply layer (33) and a channel layer (32) adjacent to the barrier layer/electron supply layer (33), wherein a cap layer (35) having the lattice constant or thermal expansion coefficient same as or similar to that of the barrier layer/electron supply layer (33) is formed on the gate insulating film (34). Thus, a stress is averaged above and below the gate insulating film (34), and the improvement of the surface profile and the improvement of resulted electric characteristics can be enhanced. COPYRIGHT: (C)2008,JPO&INPIT