Semiconductor device

A semiconductor device, comprising:

• a semiconductor layer made of first conductivity type SiC;
• 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 and that includes a first region defined adjacent to the well region and a second region defined adjacent to the first region, a depth of the source region is from 0.2 um to 1 um;
• a gate insulating film formed on the semiconductor layer and having defined therein:
• a first portion that contacts the first region of the source region;
• a second portion that contacts the well region;
• and
• a third portion that contacts the second region of the source region and that has a thickness that is greater than that of the first portion;
• and
• a gate electrode formed on the gate insulating film and opposed to the channel region of the well region where a channel is formed through the gate insulating film.