Patent ID: 7935917

Claim:
A photo detector device, comprising: a substrate; a common gate electrode over the substrate; an insulating layer over the common gate electrode and the substrate; a semiconductor layer over the insulating layer; a first diffused region and a second diffused region both disposed over the semiconductor layer and the common gate electrode, wherein the common gate electrode is between the first diffused region and the second diffused region; a third diffused region over the semiconductor layer and the common gate electrode, wherein the first diffused region, the common gate electrode and the third diffused region form a first photosensitive transistor capable of detecting an optical signal, and the second diffused region, the common gate electrode and the third diffused region form a second photosensitive transistor capable of detecting an optical signal, and wherein the common gate electrode is a first gate electrode, the device further comprising: a second gate electrode over the substrate; and a fourth diffused region over the semiconductor layer and the second gate electrode, wherein the fourth diffused region, the second gate electrode and one of the first diffused region and the second diffused region from a switching transistor capable driving the first and second photosensitive transistors.