Semiconductor device and manufacturing method thereof

Abstract

A semiconductor device (), including: a channel region () of a first conductivity type formed at a surface layer portion of a semiconductor substrate (); a source region () of a second conductivity type which is different from the first conductivity type, the source region () being formed at a rim of a trench () having a depth sufficient to penetrate through the channel region (); a drain region () of the second conductivity type formed at a region adjacent to a bottom of the trench (); a gate insulating film () formed along an inner side wall of the trench (); a gate electrode () arranged in the trench () so as to be opposed to the channel region () with the gate insulating film () interposed therebetween; a conductive layer () formed in the trench () so as to be nearer to the drain region () than the gate electrode (); and an insulating layer () surrounding the conductive layer () to electrically insulate the conductive layer () from the gate electrode () and the drain region ().