Patent ID: 7897971
Filing Date: 2011-03-01
Classification: G02F,H01L

Abstract:
1. A display device comprising: an input terminal; a pixel portion; and a protection circuit including at least a thin film transistor between the input terminal and the pixel portion; wherein the thin film transistor includes: a gate electrode; a gate insulating layer covering the gate electrode; a microcrystalline semiconductor layer over the gate insulating layer; a buffer layer over the microcrystalline semiconductor layer; a source region and a drain region over the buffer layer; a source electrode being in contact with the source region; and a drain electrode being in contact with the drain region, wherein regions of the buffer layer overlapping with the source region and the drain region are thicker than a region of the buffer layer overlapping with a channel formation region, wherein a protective insulating layer, including a first opening portion and a second opening portion is provided over the source electrode and the drain electrode, wherein the first opening portion is provided so as to reach one of the source electrode and the drain electrode, wherein the second opening portion is provided so as to reach the gate electrode, and wherein an electrode connecting the first opening portion and the second opening portion is provided over the protective insulating layer.