Patent ID: 7943935
Filing Date: 2011-05-17
Classification: H01L

Abstract:
1. A semiconductor device comprising: a thin-film transistor including transistor, the thin-film transistor including: a polycrystalline silicon layer that is disposed above a substrate, serving as an active layer, a first thin-film transistor section including a first channel region disposed in a drain-side portion of the polycrystalline silicon layer, a second thin-film transistor section including a second channel region adjacent to the first channel region with at least one of impurity-implanted region disposed between the first channel region and the second channel region, a third thin-film transistor section is formed on the source side of the second thin-film transistor section so as to be located at a position symmetrical to the position of the first thin-film transistor section, a common gate electrode that is shared by the first, second, and third thin-film transistor sections is disposed on a gate-insulating layer, wherein the first thin-film transistor section includes no lightly doped region on the source side but a lightly doped region located on the drain side; the second thin-film transistor section includes no lightly doped region on the drain or source side; and the third thin-film transistor section includes no lightly doped region on the drain side but a lightly doped n-type region located on the source side.