| 摘要 |
PROBLEM TO BE SOLVED: To provide an FET which is unlikely to cause deterioration in element to achieve higher reliability even when a high voltage is applied to between gate-drain containing a group III nitride semiconductor as a chief material.SOLUTION: A field effect transistor in which a buffer layer 11, a channel layer 12 and an electron supply layer 13 which are lattice relaxed in a growth mode parallel with a [0001] or [000-1] crystal axis are formed on a substrate 10 in this order by using a group III nitride semiconductor, and which has a source electrode 141 and a drain electrode 142 electrically connected to the channel layer 12; and a gate electrode 15 formed on the electron supply layer 13. Either layer of the buffer layer 11 and the electron supply layer 13 on the side of a group III atomic surface of the channel layer 12 has a larger a-axis length than a layer on the side of a group-V atomic surface of the channel layer 12 and the electron supply layer 13 has a band gap larger than that of the channel layer 12. |
