Patent ID: 6963109

Claim:
A semiconductor device comprising: a gate electrode formed on a first conductive type semiconductor substrate through a gate oxide film; a first low concentration drain region of a second conductive type provided adjacent to one end of said gate electrode; a second low concentration drain region of the second conductive type, provided in said first low concentration drain region, said second low concentration drain region being disposed close to an outer boundary of said first low concentration drain region and being higher in impurity concentration than at least an impurity concentration of the first low concentration drain region, wherein at least part of said second low concentration drain region is extended to an area under said gate electrode; a high concentration source region of the second conductive type provided adjacent to another end of said gate electrode, wherein the high concentration source region is in direct contact with the substrate; and a high concentration drain region of the second conductive type formed in said second low concentration drain region, said high concentration drain region being spaced away a predetermined distance from said gate electrode and being higher in impurity concentration than the second low concentration drain region.