JPS6457759A - Field-effect-type semiconductor device - Google Patents

Abstract

PURPOSE:To prevent increase of gate-source or gate-drain capacitance and to prevent deterioration in high-frequency characteristics, by providing a gate electrode which is in contact with a channel region in an area smaller than the size of the gate electrode. CONSTITUTION:An N-type channel region 5 in a semiconductor substrate 7 on which a gate electrode 2 is carried has a surface 5a to be in contact with the gate electrode 2 and the surface 5a has a length or effective gate length Lg2 that is smaller than an actual length Lg3 of the gate electrode 2. In other words, shoulders 5b and 5c of the N-type channel region 5 are inclined such that they reach down to an N<+> type source region 4 and an N<+> type drain region 6, respectively. Thereby, the N<+> type source and drain regions 4 and 6 are electrically isolated from the gate electrode 2. In this manner, the distance Lsd between the source and the drain can be shorter than the effective length Lg of the gate electrode without need of using any dielectric for isolating the N<+> type source and drain regions from the gate electrode 2 and without involving increase of gate-source capacitance Cgs and source-drain capacitance Cgd.