Patent ID: 7714388

Claim:
A semiconductor device comprising: an insulation layer; a FIN-type semiconductor layer provided on the insulation layer and including a floating body region in an electrically floating state and including a source region and a drain region at both sides of the floating body region; gate insulation films provided on both side surfaces of the floating body region; gate electrodes provided on both side surfaces of the floating body regions via the gate insulation films, and extending in a direction in which the FIN-type semiconductor layer extends; a source electrode and a drain electrode respectively contacting with the upper surface of the source region and the drain region; and protection films provided between a side surface of the source region and one of the gate electrodes and between a side surface of the drain region and one of the gate electrodes, one of the protection films contacting the side surfaces of the source region, and the other of the protection films contacting the side surface of the drain region, wherein in the cross section of the FIN-type semiconductor layer in parallel with the surface of the insulation layer, a thickness of the FIN-type semiconductor layer in the floating body region is smaller than a thickness of the FIN-type semiconductor layer in the source and the drain regions, and thickness of the protection films in a direction perpendicular to the side surfaces of the source or the drain region is greater than thickness of the gate insulation films in a direction perpendicular to the side surfaces of the floating body region.