Patent ID: 7973338

Claim:
A hetero junction field effect transistor, comprising: a channel layer of a nitride based, group III-V compound semiconductor; a hetero characteristic improvement layer of a nitride based, group III-V compound semiconductor overlying and physically contacting said channel layer; a first layer of a nitride based, group III-V compound semiconductor, overlying and physically contacting said hetero characteristic improvement layer; a second layer of a nitride of a rare earth element, overlying and physically contacting said first layer; a pair of third layers of a nitride based, group III-V compound semiconductor, overlying and physically contacting said second layer, said third layers being spaced from each other; a two dimensional electron gas layer provided between said channel layer and said hetero characteristic improvement layer; a gate electrode disposed between said third layers on at least a region of said second layer; and a source electrode overlying one of said third layers and a drain electrode overlying an other of said third layers.