Thin film semiconductor device
View Patent ↗According to one embodiment, provided is a thin film transistor with which it is possible to reduce the leakage current and thereby, for a liquid crystal display device, to ensure a good display quality. The thin film transistor includes a semiconductor layer, gate electrodes, first light-blocking electrodes, and second light-blocking electrodes. The first light-blocking electrodes are disposed opposite to the gate electrodes with respect to the semiconductor layer and opposed to channel regions to block light incident into the channel regions. The second light-blocking electrodes are disposed opposite to the semiconductor layer with respect to the gate electrodes, arranged to block light incident into the channel regions, and electrically connected with one of a signal line and a pixel electrode.
1. A thin film semiconductor device for use in a display device, the thin film semiconductor device arranged to drive a pixel electrode, with which an image is displayed, according to a signal voltage applied on a signal line, the thin film semiconductor device comprising:
a semiconductor layer including a channel region and a pair of contact regions disposed with the channel region therebetween and doped with an impurity at a concentration relatively higher than in the channel region, wherein one of the contact regions is electrically connected to the signal line, while the other is electrically connected to the pixel electrode;
a gate electrode disposed at a position facing the channel region of the semiconductor layer; and
a light-blocking electrode arranged to block light incident into the channel region, wherein
the light-blocking electrode consists of:
a first light-blocking electrode disposed opposite to the gate electrode with respect to the semiconductor layer and facing the channel region to block light incident into the channel region; and
a second light-blocking electrode disposed opposite to the semiconductor layer with respect to the gate electrode, arranged to block light incident into the channel region, and electrically connected with one of the signal line and the pixel electrode, and wherein
the gate electrode is formed in a pair, the pair of gate electrodes electrically connected to each other, and wherein
the channel region and the second light-blocking electrode are each formed in a pair correspondingly to the pair of gate electrodes, and wherein
one of the pair of second light-blocking electrodes is electrically connected with the signal line, while the other electrically connected with the pixel electrode.
2. The thin film semiconductor device according to claim 1 , wherein the first light-blocking electrode is formed in a pair correspondingly to the pair of gate electrodes, the pair of first light-blocking electrodes extending to positions facing the pair of respective contact regions.
3. The thin film semiconductor device according to claim 1 , wherein the first light-blocking electrode is formed in a manner facing both of the pair of gate electrodes and extends to positions facing the pair of respective contact regions.
4. The thin film semiconductor device according to claim 1 , wherein
the channel region and the first light-blocking electrode are each formed in a pair correspondingly to the pair of gate electrodes, and wherein
the second light-blocking electrode is formed in a manner facing both of the pair of channel regions and electrically connected with one of the signal line and the pixel electrode.
5. The thin film semiconductor device according to claim 1 , further comprising an intermediate region positioned between the channel region and each of the contact regions.