Patent ID: 8378391

Claim:
A semiconductor device comprising a pixel portion, the pixel portion comprising: a photoelectric conversion element portion buried in a substrate comprising a silicon semiconductor; a transfer transistor electrically connected to the photoelectric conversion element portion; a signal charge storage portion electrically connected to the transfer transistor; a reset transistor electrically connected to the signal charge storage portion; and an amplifier transistor electrically connected to the signal charge storage portion, wherein a channel formation region of the transfer transistor comprises a first oxide semiconductor layer, a channel formation region of the reset transistor comprises a second oxide semiconductor layer, and a channel formation region of the amplifier transistor comprises the silicon semiconductor, wherein a first conductive layer is provided over the substrate with an insulating layer interposed therebetween and in contact with the first oxide semiconductor layer and the second oxide semiconductor layer, and wherein the signal charge storage portion includes the silicon semiconductor and the first conductive layer with the insulating layer interposed therebetween.