FIELD EFFECT TRANSISTOR

摘要

PROBLEM TO BE SOLVED: To make it possible to inhibit limitation in voltage resistance and decrease in operation speed in a HEMT.SOLUTION: In a field effect transistor, a channel region 102 includes a first channel layer 121, a second channel layer 122 and a third channel layer 123 which are laminated. Each of the first channel layer 121, the second channel layer 122 and the third channel layer 123 composed of a compound semiconductor, and the second channel layer 122 has bandgap energy smaller than that of the first channel layer 121 and the third channel layer 123 has bandgap energy smaller than that of the second channel layer 122.