Patent ID: 7705371

Claim:
A field effect transistor comprising: a layered structure of nitride semiconductors formed on a substrate and including a capping layer made of a compound represented by a general formula of In x Al y Ga 1-y N (wherein 0<x≦1, 0≦y<1 and 0<x+y≦1); a non-alloy source electrode and a non-alloy drain electrode formed directly on said capping layer and spaced from each other; and a gate electrode, wherein said layered structure of nitride semiconductors includes an electron supplying layer formed under said capping layer, said capping layer has an opening formed in a region between said source electrode and said drain electrode for exposing said electron supplying layer therein, said gate electrode is formed on a portion of said electron supplying layer exposed in said opening, and said gate electrode, said source electrode and said drain electrode are made of the same material.