Patent ID: 8766277

Claim:
A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a drift layer of the first conductivity type disposed on the semiconductor substrate; a source region of the first conductivity type disposed on an upper surface of the drift layer; a trench reaching an intermediate depth of the drift layer from an upper surface of the source region; a gate region of a second conductivity type being opposite to the first conductivity type disposed at a sidewall and a bottom surface of the trench in the drift layer below the source region; a first semiconductor region of the first conductivity type containing nitrogen as an impurity and disposed on the gate region disposed at the sidewall and the bottom surface of the trench; and a second semiconductor region of the first conductivity type containing nitrogen as an impurity and disposed on a side surface of the source region and above the first semiconductor region, wherein an impurity concentration of the first semiconductor region is lower than an impurity concentration of the second semiconductor region, and wherein the impurity concentration of the second semiconductor region is higher than an impurity concentration of the source region.