Silicon-on-insulator metal oxide semiconductor device having conductive

Abstract

A field effect transistor comprises source, drain and channel regions in a semiconductor layer formed on an insulating substrate. An island-shaped semiconductor layer of a first conductivity type is formed on a major surface of the insulating substrate and isolated from the surroundings. Source and drain regions of a second conductivity type are formed spaced apart from each other in the island-shaped semiconductor layer so as to define the channel region having a part of a major surface of the island-shaped semiconductor layer as a channel surface. A gate electrode is formed on the channel surface through an insulating film. A sidewall insulating film is formed on a sidewall of other region than the source region in the island-shaped semiconductor layer. A semiconductor sidewall layer of the first conductivity type is formed on a sidewall of the island-shaped semiconductor layer corresponding to the source region and the sidewall insulating film. Potentials of the source region and the semiconductor sidewall layer are held the same. A sidewall leakage current due to a parasitic MOS transistor is reduced. A potential barrier near an end portion of the source region is stabilized and reduction of a breakdown voltage between the source and drain can be prevented. A SOI-MOS transistor having stable electrical characteristics can be obtained.