| 摘要 |
PROBLEM TO BE SOLVED: To provide a field effect transistor which attains a high threshold voltage and low ON resistance, and in which parallel conduction is suppressed.SOLUTION: The field effect transistor has a buffer layer 602 of group III nitride, a channel layer 603, a barrier layer 605 and a cap layer 606 which are laminated in this order on a substrate 601. An upper surface of each semiconductor layer is a group III atom surface perpendicular to a (0001) crystal axis, the buffer layer 602 is lattice-relaxed, and the barrier layer 605 has tensile strain and the channel layer 603 and cap layer 606 have compressive strain, or the channel layer 603 is lattice-relaxed and the cap layer 606 has tensile strain. The cap layer 606, a gate insulating film 607 and a gate electrode 608 are laminated in this order in a part of a region on the barrier layer 605, and a source electrode 609 and a drain electrode 610 are formed in the other region. |
