Patent ID: 7119412

Claim:
A semiconductor device, comprising: a semiconductor substrate; an element isolation insulating film formed on a surface of said semiconductor substrate which defines a first active region, a surface of said element isolation insulating film being at a position lower than a surface of said first active region, and an edge portion of said first active region being rounded; and a first field effect transistor formed within said first active region, wherein a second active region is defined at a position separate from said first active region by said element isolation insulating film, a second field effect transistor is formed within said second active region, a gate insulating film of said second field effect transistor is thicker than a gate insulating film of said first field effect transistor, and a step between the surface of said element isolation insulating film and a surface of said second active region is smaller than a step between the surface of said element isolation insulating film and the surface of said first active region.