Patent ID: 7800114
Filing Date: 2010-09-21
Classification: H01L,Y10S

Abstract:
1. A semiconductor device comprising: a substrate having an insulating surface; an island-like semiconductor layer over the substrate, the island-like semiconductor layer including a source region, a drain region, low concentration impurity regions of which an impurity concentration is lower than that of the source and drain regions, and a channel region; a gate insulating film formed over the island-like semiconductor layer; a first gate electrode formed over the gate insulating film; a second gate electrode of which a channel length direction is shorter than that of the first gate electrode, the second gate electrode being over the first gate electrode; and sidewalls formed of an insulating film, the sidewalls being located on opposite skies of the second gate electrode in a channel length direction, wherein the first gate electrode partially overlaps the low concentration impurity regions with the gate insulating film interposed therebetween, wherein a length of the first gate electrode that overlaps the low concentration impurity regions is substantially equal to a length of the sidewalls, and wherein the low concentration impurity regions are formed between the channel region and the source region and between the channel region and the drain region.