Patent ID: 9257521
Filing Date: 2016-02-09
CPC Classification: H01L

Claim Text:
1. A semiconductor device, comprising: a semiconductor layer made of first conductivity type; a well region that is a second conductivity type well region formed on a surface layer portion of the semiconductor layer and that has a channel region defined therein; a source region that is a first conductivity type source region formed on a surface layer portion of the well region; a trench formed in the semiconductor layer that extends downwardly from the upper surface of the source region to pass through the source region and the well region; a gate insulating film formed on the inner surface of the trench, the gate insulating film including a bump portion which changes a thickness of the gate insulating film at the source region, the bump portion being formed on a side surface of the trench, and being adjacent to the channel region; and a gate electrode opposed to the channel region of the well region where a channel is formed through the gate insulating film.