Patent ID: 7157779

Claim:
A semiconductor device comprising: a semiconductor substrate of a first general conductivity type; a gate insulation film disposed on the semiconductor substrate; a gate electrode disposed on the gate insulation film; a first low impurity concentration drain layer formed in a surface of the semiconductor substrate and extending below the gate electrode, the first low impurity concentration drain layer being of a second general conductivity type; a surface injection layer formed in the surface of the semiconductor substrate and covering part of the first low impurity concentration drain layer, the surface injection layer having an impurity concentration higher than an impurity concentration of the first low impurity concentration drain layer and being of the second general conductivity type; a high impurity concentration drain layer formed in the surface of the semiconductor substrate and electrically connected to the first low impurity concentration drain layer, the high impurity concentration drain layer being of the second general conductivity type; and a second low impurity concentration drain layer formed in the semiconductor substrate shallower than the first low impurity concentration drain layer and deeper than the surface injection layer, the second low impurity concentration drain layer having an impurity concentration lower than the impurity concentration of the first low impurity concentration drain layer and being of the second conductivity type.