| 摘要 |
A first group III nitride semiconductor layer has a low carbon concentration region having a carbon concentration of less than 1×1017 cm-3, and located in a region under an edge of a gate electrode closer to a drain electrode, a thickness d2 of the low carbon concentration region satisfies Vm/(110·d1)@d2<Vm/(110·d1)+0.5 where d1 is a thickness of a nitride semiconductor layer including the first group III nitride semiconductor layer and the second group III nitride semiconductor layer, and Vm is an operating breakdown voltage, and a ratio of Ron to Ron0, which is an index of a current collapse value, satisfies Ron/Ron0@3 where Ron0 is an on-state resistance in a relaxed state, and Ron is an on-state resistance measured 100 mus after a transition from an off state to an on state under an operating voltage Vm. |
