High breakdown voltage field effect transistor

Abstract

A semiconductor device includes a drain electrode, a source electrode, and a gate electrode on a semiconductor substrate; a semiconductor layer on a region of the semiconductor substrate and including a first dopant concentration region on which the gate electrode is centrally disposed; a second dopant concentration region more heavily doped than the first dopant concentration region, disposed adjacent the first dopant concentration region and having a length toward the drain electrode; third dopant concentration regions, more heavily doped than the second dopant concentration region, respectively disposed adjacent the second dopant concentration region at drain side and adjacent the first dopant concentration region at the source side; a drain electrode disposed on one of the third dopant concentration regions; and a source electrode disposed on the other of the third dopant concentration regions. Even when the second dopant concentration region is etched while producing a sidewall in producing the semiconductor device, the depth of the surface depletion layer on the etched part is shallow so that channel confinement is relaxed. In addition, even when an electric field is concentrated toward the drain side of the first dopant concentration region, the electric field at the third dopant concentration region is relaxed.