| 摘要 |
<p>PROBLEM TO BE SOLVED: To suppress falling, at a high temperature, of a drain current of a depletion type field effect transistor that uses a nitride semiconductor.SOLUTION: A field effect transistor includes a first barrier wall layer 102 comprising a second nitride semiconductor in which a main surface is a (0001) surface, a second barrier wall layer 105 and a third barrier wall layer 106 which have a layer thickness of 1.5-5 nm, and are formed on the first barrier wall layer 102 of a source formation region 122 and a drain formation region 123 which sandwich a gate formation region 121, being made from a third nitride semiconductor having a larger band gap energy than the seconde nitride semiconductor, and a fourth barrier wall layer 107 and a fifth barrier wall layer 108 which are formed over them and made from the second nitride semiconductor containing an impurity introduction region 171 and an impurity introduction region 181 on its lower side. The layer thickness of the first barrier wall layer 102 of the gate formation region 121 is a thickness to form a secondary electron in the first barrier wall layer 102 of the gate formation region 121.</p> |
