MIS semiconductor device formed by utilizing SOI substrate having a semiconductor thin film formed on a substrate through an insulating layer

摘要

The present invention is directed to a MIS semiconductor device having a semiconductor layer formed on an insulating substrate and a gate electrode formed on this semiconductor layer through a gate insulating film, which is provided with a semiconductor region of a second conductivity type or a metal layer formed adjacent to a source region of a first conductivity type but separated from a channel region, thereby suppressing degradation of breakdown voltage caused by impact ionization, which is a defect of the MIS semiconductor device formed on an SOI substrate, to improve the reliability of this kind of MIS semiconductor devices.