Patent ID: 8618578
Filing Date: 2013-12-31
Classification: H01L

Abstract:
1. A field effect transistor comprising: a nitride-based semiconductor multi-layer structure; a source electrode; a drain electrode; a protective film; and a gate electrode, wherein the nitride-based semiconductor multi-layer structure includes at least a base layer made of Al the source electrode, the drain electrode, and the protective film are provided over a surface of the nitride-based semiconductor multi-layer structure, the gate electrode is provided in a recess structure, which is formed by etching the entire protective film, the entire second electron supply layer, and a portion of the threshold value control layer in a portion of a space between the source electrode and the drain electrode, directly or with a gate insulating film interposed therebetween, and the Al composition of each layer in the nitride-based semiconductor multi-layer structure satisfies 0≦X≦Y<1 and 0<Z≦Y≦1.