Patent ID: 7868355
Filing Date: 2011-01-11
Classification: H01L

Abstract:
1. A hetero field effect transistor comprising: a main semiconductor region comprising a first semiconductor layer and a second semiconductor layer formed on the first semiconductor layer to allow a generation of a two-dimensional carrier gas layer of a first conductive type on a heterojunction interface between the first semiconductor layer and the second semiconductor layer; a source electrode formed on the main semiconductor region; a drain electrode formed on the main semiconductor region and separated from the source electrode; a third semiconductor layer of a second conductive type different from the first conductive type, the third semiconductor layer being formed on a second semiconductor layer and located between the source electrode and the drain electrode; a fourth semiconductor layer formed on or above the first semiconductor layer and made of a compound semiconductor which has a diffusion coefficient smaller than that of the second semiconductor layer; a gate electrode formed on the third semiconductor layer; and a diffusion layer of the second conductive type formed on the second semiconductor layer at a region immediately below the gate electrode.