Semiconductor device

A semiconductor device comprising:

• a semiconductor layer of a first conductivity type having a first main surface at one side and a second main surface at another side;
• a trench gate structure including a gate trench formed in the first main surface of the semiconductor layer, and a gate electrode embedded in the gate trench via a gate insulating layer;
• a trench source structure including a source trench formed deeper than the gate trench and formed across an interval from the gate trench in the first main surface of the semiconductor layer, a source electrode embedded in the source trench, and a well region of a second conductivity type formed in a region of the semiconductor layer along the source trench, a ratio of a depth of the trench source structure with respect to a depth of the trench gate structure being not less than 1.5 and not more than 4.0;
• a body region of the second conductivity type formed in a region of a surface layer portion of the first main surface of the semiconductor layer between the gate trench and the source trench;
• a source region of the first conductivity type formed in a surface layer portion of the body region;
• and
• a drain electrode connected to the second main surface of the semiconductor layer;
• and
• wherein the trench source structure includes a barrier forming layer interposed in a region between the source trench and the source electrode and having a higher potential barrier than a potential barrier between the well region and the source electrode, and
• the barrier forming layer includes an insulating barrier forming layer made of an insulating material, and a conductive barrier forming layer made of a conductive material differing from a conductive material of the source electrode.