Method of producing a metal-oxide semiconductor device

Abstract

The present invention relates to a method of producing a metal-oxide semiconductor device with improved capacity for preventing an actuation of a parasitic bipolar transistor. In the present invention, a metal-oxide seminconductor device is produced through a process in which a single conductive semiconductor region with low-impurity density, on top of which region a gate electrode is provided via a gate-insulating film, consists of two sub-layers with different specific resistance. The upper sub-layer of the region has a significantly lower specific resistance than the lower sub-layer of the region. When a lifetime-reducing agent for reducing the reverse-recovery time of a built-in diode is diffused into the single conductive semiconductor region with low-impurity density, the lifetime-reducing agent concentrates in the upper sub-layer of the region, thereby increasing the specific resistance of the upper sub-layer. Because the specific resistance of the upper sub-layer is initially low, however, the increase in the specific resistance is compensated, and the on-resistance at the time of conduction of the metal-oxide semiconductor device does not increase as a whole. Consequently, the reverse-recovery time of the built-in diode is reduced without an overall increase in the on-resistance, thereby preventing an actuation of the parasitic bipolar transistor without additional power loss.