Patent ID: 8334537

Claim:
A display device comprising: a gate electrode; a gate insulating film formed over the gate electrode; a microcrystalline semiconductor film formed over the gate insulating film; a buffer layer which is formed over the microcrystalline semiconductor film and has a concave portion; source and drain regions formed over the buffer layer; a source, electrode over the source region; and a drain electrode over the drain region, wherein: the buffer layer is formed of an amorphous semiconductor film; a part of the source region is in contact with the source electrode and the other part of the source region is not in contact with the source electrode; a part of the drain region is in contact with the drain electrode and the other part of the drain region is not in contact with the drain electrode; the buffer layer extends beyond an outer side edge of the source region and an outer side edge of the drain region; and an end portion of the source region and an end portion of the drain region which are overlapped with the gate electrode are aligned with side faces of the concave portion of the buffer layer.