Semiconductor device including image sensor
AssigneeSemiconductor Energy Laboratory Co., Ltd.
InventorsJun Koyama, Shunpei Yamazaki
Life of this patent
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Abstract
A solid-state image sensor which holds a potential for a long time and includes a thin film transistor with stable electrical characteristics is provided. When the off-state current of a thin film transistor including an oxide semiconductor layer is set to 1×10−13 A or less and the thin film transistor is used as a reset transistor and a transfer transistor of the solid-state image sensor, the potential of the signal charge storage portion is kept constant, so that a dynamic range can be improved. When a silicon semiconductor which can be used for a complementary metal oxide semiconductor is used for a peripheral circuit, a high-speed semiconductor device with low power consumption can be manufactured.
Claims18
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.
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,
- wherein the signal charge storage portion includes the silicon semiconductor and the first conductive layer with the insulating layer interposed therebetween, and
- wherein a second conductive layer is provided over the substrate with the insulating layer interposed therebetween and in contact with the first oxide semiconductor layer and the photoelectric conversion element portion.
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,
- wherein the signal charge storage portion includes the silicon semiconductor and the first conductive layer with the insulating layer interposed therebetween,
- wherein a second conductive layer is provided over the substrate with the insulating layer interposed therebetween and in contact with the first oxide semiconductor layer and the photoelectric conversion element portion,
- wherein a third conductive layer is provided over the substrate with the insulating layer interposed therebetween and in contact with the second oxide semiconductor layer, and
- wherein a field oxide film is formed in the substrate and in contact with one of a source and a drain of the amplifier transistor.
Dependencies are inferred from the claim text.