Patent ID: 7719043

Claim:
A semiconductor device comprising a Fin type field effect transistor which comprises a protrusive semiconductor layer protruding upward with respect to a substrate plane, a gate electrode extending from the upper part of the protrusive semiconductor layer onto facing opposite side surfaces thereof so as to straddle the protrusive semiconductor layer, a gate insulating film interposed between the gate electrode and said protrusive semiconductor layer, and a pair of source and drain regions provided in said protrusive semiconductor layer, wherein the semiconductor device comprises on a semiconductor substrate an element forming region having at least one Fin type field effect transistor, a trench provided on the semiconductor substrate for separating the element forming region from another element forming region, and an element isolation insulating film provided in the trench; and said element forming region comprises a shallow substrate flat surface formed by digging to a depth shallower than the bottom surface of said trench and deeper than the upper surface of said semiconductor substrate, a semiconductor raised portion protruding with respect to the substrate flat surface and formed of a part of said semiconductor substrate, and an insulating film provided on said shallow substrate flat surface; and the protrusive semiconductor layer of said Fin type field effect transistor is formed of a portion protruding with respect to the insulating film of said semiconductor raised portion.