SEMICONDUCTOR DEVICE

• US 20110204371A1
• Filed: 02/15/2011
• Published: 08/25/2011
• Est. Priority Date: 02/19/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: KUROKAWA, Yoshiyuki, KOZUMA, Munehiro
• Granted Patent: US 8,716,712 B2
• Time in Patent Office: Days
• US Class Current: 257/59
• CPC Class Codes: H01L 27/14603 Special geometry or disposition of pixel-elements, address-lines or gate-electrodes
• CPC Class Codes: H01L 27/14607 Geometry of the photosensitive area
• CPC Class Codes: H01L 27/14609 Pixel-elements with integrated switching, control, storage or amplification elements scanning details of imagers (circuitry of solid-state image sensors H04N25/00); circuitry of imagers H04N25/70
• CPC Class Codes: H01L 27/14643 Photodiode arrays; MOS imagers

Abstract

An object of the invention is to improve the accuracy of light detection in a photosensor, and to increase the light-receiving area of the photosensor. The photosensor includes: a light-receiving element which converts light into an electric signal; a first transistor which transfers the electric signal; and a second transistor which amplifies the electric signal. The light-receiving element includes a silicon semiconductor, and the first transistor includes an oxide semiconductor. The light-receiving element is a lateral-junction photodiode, and an n-region or a p-region included in the light-receiving element overlaps with the first transistor.

Claims

1. A semiconductor device comprising:

a light-receiving element configured to convert light into an electric signal;

a first transistor configured to transfer the electric signal; and

a second transistor configured to amplify the transferred electric signal,

wherein the first transistor includes an oxide semiconductor.

2. A semiconductor device according to claim 1, further comprising an insulating film interposed between the first transistor and the light-receiving element.

4. A semiconductor device according to claim 1, wherein the light-receiving element and a channel formation region of the second transistor are made from a same semiconductor layer.

6. A semiconductor device according to claim 1, wherein the light-receiving element and the second transistor include silicon.

8. A semiconductor device according to claim 1, further comprising a third transistor configured to control reading of an output signal generated by the second transistor.

10. A semiconductor device according to claim 1, further comprising a fourth transistor configured to control reset of a gate potential of the second transistor;

wherein a channel formation region of the fourth transistor is made from a same layer as a channel formation region of the first transistor.

12. A semiconductor device according to claim 1, further comprising a wiring formed over a light-receiving portion of the light-receiving element,

wherein the wiring includes a light-transmitting material.

3. A semiconductor device comprising:

a photodiode including a semiconductor film formed on a surface, the semiconductor film comprising an n-region and a p-region each in contact with the surface;

a first transistor configured to transfer an electric signal generated by the photodiode; and

a second transistor configured to amplify the transferred electric signal,

an insulating film interposed between the first transistor and the second transistor and between the first transistor and the photodiode;

wherein the first transistor includes an oxide semiconductor and overlaps one of the n-region and the p-region of the photodiode when seen from above.

5. A semiconductor device according to claim 3, wherein the n-region, the p-region and a channel formation region of the second transistor are made from the same semiconductor layer.

7. A semiconductor device according to claim 3, wherein the photodiode and the second transistor include silicon.

9. A semiconductor device according to claim 3, further comprising a third transistor configured to control reading of an output signal generated by the second transistor.

11. A semiconductor device according to claim 3, further comprising a fourth transistor configured to control reset of a gate potential of the second transistor;

wherein a channel formation region of the fourth transistor is made from a same layer as a channel formation region of the first transistor.

13. A semiconductor device according to claim 3, further comprising a wiring formed over the photodiode,

wherein the wiring includes a light-transmitting material.

14. A semiconductor device comprising:

a light-receiving element configured to convert light into an output electric signal;

a first transistor, one of a source and a drain of the first transistor being electrically connected to an output terminal of the light-receiving element; and

a second transistor, a gate of the second transistor being electrically connected to the other of the source and the drain of the first transistor,

wherein the first transistor includes an oxide semiconductor.

15. A semiconductor device according to claim 14, further comprising an insulating film interposed between the first transistor and the light-receiving element.

17. A semiconductor device according to claim 14, wherein the light-receiving element and a channel formation region of the second transistor are made from a same semiconductor layer.

19. A semiconductor device according to claim 14, wherein the light-receiving element and the second transistor include silicon.

21. A semiconductor device according to claim 14, further comprising a third transistor, one of a source and a drain of the third transistor being electrically connected to one of a source and a drain of the second transistor.

23. A semiconductor device according to claim 14, further comprising a fourth transistor, one of a source and a drain of the fourth transistor being electrically connected to a gate of the second transistor;

wherein a channel formation region of the fourth transistor is made from a same layer as a channel formation region of the first transistor.

25. A semiconductor device according to claim 14, further comprising a wiring formed over a light-receiving portion of the light-receiving element,

wherein the wiring includes a light-transmitting material.

16. A semiconductor device comprising:

a photodiode including a semiconductor film formed on a surface, the semiconductor film comprising an n-region and a p-region each in contact with the surface;

a first transistor, one of a source and a drain of the first transistor being electrically connected to an output terminal of the photodiode; and

a second transistor, a gate of the second transistor being electrically connected to the other of the source and the drain of the first transistor,

an insulating film interposed between the first transistor and the second transistor and between the first transistor and the photodiode;

wherein the first transistor includes an oxide semiconductor and overlaps one of the n-region and the p-region of the photodiode when seen from above.

18. A semiconductor device according to claim 16, wherein the n-region, the p-region and a channel formation region of the second transistor are made from the same semiconductor layer.

20. A semiconductor device according to claim 16, wherein the photodiode and the second transistor include silicon.

22. A semiconductor device according to claim 16, further comprising a third transistor, one of a source and a drain of the third transistor being electrically connected to one of a source and a drain of the second transistor.

24. A semiconductor device according to claim 16, further comprising a fourth transistor, one of a source and a drain of the fourth transistor being electrically connected to a gate of the second transistor;

wherein a channel formation region of the fourth transistor is made from a same layer as a channel formation region of the first transistor.

26. A semiconductor device according to claim 16, further comprising a wiring formed over a light-receiving portion of the photodiode,

wherein the wiring includes a light-transmitting material.