Patent ID: 6844593
Filing Date: 2005-01-18
Classification: H01L

Abstract:
1. A semiconductor device comprising: a semiconductor substrate of a first conductivity type; a gate insulation film disposed on a surface of the semiconductor substrate; a gate electrode disposed on the gate insulation film; a source layer of a second conductivity type formed in the surface of the semiconductor substrate and adjacent one end of the gate electrode; a high impurity drain layer of the second conductivity type formed in the surface of the semiconductor substrate and apart from another end of the gate electrode; a low impurity drain layer of the second conductivity type formed in the surface of the semiconductor substrate, the low impurity drain layer being disposed at least between the high impurity drain layer and said another end of the gate electrode, and the low impurity drain layer having an impurity concentration lower than an impurity concentration of the high impurity drain layer; and a buried layer of the first conductivity type formed in a region deeper than the high impurity drain layer and forming a PN junction with the high impurity drain layer, wherein no part of the low impurity drain layer is disposed under the high impurity drain layer.