SEMICONDUCTOR DEVICE

• US 20130075722A1
• Filed: 09/13/2012
• Published: 03/28/2013
• Est. Priority Date: 09/23/2011
• Status: Abandoned Application

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: YAMAZAKI, Shunpei, ISOBE, Atsuo, OKAZAKI, Yutaka, HATANO, Takehisa, TEZUKA, Sachiaki, HONDO, Suguru, SAITO, Toshihiko
• Application Number:
  US13/613,192
• Publication Number:
  US 20130075722A1
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 29/41733 for thin film transistors with insulated gate
• CPC Class Codes: H01L 29/42384 for thin film field effect transistors, e.g. characterised by the thickness or the shape of the insulator or the dimensions, the shape or the lay-out of the conductor
• CPC Class Codes: H01L 29/78618 characterised by the drain or the source properties, e.g. the doping structure, the composition, the sectional shape or the contact structure silicide contacts, electrodes in general H01L29/458
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

A highly reliable structure for high-speed response and high-speed driving of a semiconductor device, in which on-state characteristics of a transistor are increased is provided. In the coplanar transistor, an oxide semiconductor layer, a source and drain electrode layers including a stack of a first conductive layer and a second conductive layer, a gate insulating layer, and a gate electrode layer are sequentially stacked in this order. The gate electrode layer is overlapped with the first conductive layer with the gate insulating layer provided therebetween, and is not overlapped with the second conductive layer with the gate insulating layer provided therebetween.

Claims

1. A semiconductor device comprising:

an oxide semiconductor layer provided over a substrate comprising an insulating surface;

a first conductive layer provided partly over the oxide semiconductor layer;

a second conductive layer provided partly over the first conductive layer;

a gate insulating layer provided over the oxide semiconductor layer, the first conductive layer, and the second conductive layer; and

a gate electrode layer provided over the oxide semiconductor layer with the gate insulating layer provided therebetween,

wherein the gate electrode layer is overlapped with the first conductive layer with the gate insulating layer provided therebetween, and is not overlapped with the second conductive layer with the gate insulating layer provided therebetween.

2. The semiconductor device according to claim 1, wherein a thickness of the first conductive layer is greater than or equal to 5 nm and less than or equal to 20 nm.

3. The semiconductor device according to claim 1, wherein a thickness of the gate insulating layer is greater than or equal to 10 nm and less than or equal to 20 nm.

4. The semiconductor device according to claim 1, wherein a thickness of the oxide semiconductor layer is greater than or equal to 5 nm and less than or equal to 20 nm.

5. The semiconductor device according to claim 1, wherein a buffer layer is provided over the substrate comprising the insulating surface.

6. The semiconductor device according to claim 5, wherein the buffer layer comprises an oxide of at least one element selected from the group consisting of aluminum, gallium, zirconium, hafnium, and a rare-earth element.

7. The semiconductor device according to claim 1, wherein the oxide semiconductor layer comprises crystals whose c-axes are aligned.

8. The semiconductor device according to claim 1, wherein the second conductive layer is provided partly over the oxide semiconductor layer.

9. A semiconductor device comprising:

an oxide semiconductor layer provided over a substrate comprising an insulating surface;

a first conductive layer provided partly over the oxide semiconductor layer;

a second conductive layer provided partly over the first conductive layer;

an insulating layer provided over the second conductive layer;

a gate insulating layer provided over the oxide semiconductor layer, the first conductive layer, the second conductive layer, and the insulating layer; and

a gate electrode layer provided over the oxide semiconductor layer with the gate insulating layer provided therebetween,

wherein the gate electrode layer is overlapped with the first conductive layer with the gate insulating layer provided therebetween, and is not overlapped with the second conductive layer with the gate insulating layer provided therebetween.

10. The semiconductor device according to claim 9, wherein a thickness of the first conductive layer is greater than or equal to 5 nm and less than or equal to 20 nm.

11. The semiconductor device according to claim 9, wherein a thickness of the gate insulating layer is greater than or equal to 10 nm and less than or equal to 20 nm.

12. The semiconductor device according to claim 9, wherein a thickness of the oxide semiconductor layer is greater than or equal to 5 nm and less than or equal to 20 nm.

13. The semiconductor device according to claim 9, wherein a buffer layer is provided over the substrate comprising the insulating surface.

14. The semiconductor device according to claim 13, wherein the buffer layer comprises an oxide of at least one element selected from the group consisting of aluminum, gallium, zirconium, hafnium, and a rare-earth element.

15. The semiconductor device according to claim 9, wherein the oxide semiconductor layer comprises crystals whose c-axes are aligned.

16. A semiconductor device comprising:

an oxide semiconductor layer provided over a substrate comprising an insulating surface;

a first conductive layer provided partly over the oxide semiconductor layer;

an insulating layer provided partly over the first conductive layer;

a second conductive layer provided partly over the insulating layer and is in contact with the first conductive layer in an opening in the insulating layer;

a gate insulating layer provided over the oxide semiconductor layer, the first conductive layer, the second conductive layer, and the insulating layer; and

a gate electrode layer provided over the oxide semiconductor layer with the gate insulating layer provided therebetween,

wherein the gate electrode layer is overlapped with the first conductive layer with the gate insulating layer provided therebetween, and is not overlapped with the second conductive layer with the gate insulating layer provided therebetween.

17. The semiconductor device according to claim 16, wherein a thickness of the first conductive layer is greater than or equal to 5 nm and less than or equal to 20 nm.

18. The semiconductor device according to claim 16, wherein a thickness of the gate insulating layer is greater than or equal to 10 nm and less than or equal to 20 nm.

19. The semiconductor device according to claim 16, wherein a thickness of the oxide semiconductor layer is greater than or equal to 5 nm and less than or equal to 20 nm.

20. The semiconductor device according to claim 16, wherein a buffer layer is provided over the substrate comprising the insulating surface.

21. The semiconductor device according to claim 20, wherein the buffer layer comprises an oxide of at least one element selected from the group consisting of aluminum, gallium, zirconium, hafnium, and a rare-earth element.

22. The semiconductor device according to claim 16, wherein the oxide semiconductor layer comprises crystals whose c-axes are aligned.

23. A semiconductor device comprising:

a substrate comprising an insulating surface;

an insulating layer partly comprising an embedded conductive layer over the insulating surface;

an oxide semiconductor layer over the insulating layer;

a first conductive layer provided partly over the oxide semiconductor layer;

a second conductive layer provided partly over the first conductive layer;

a gate insulating layer provided over the oxide semiconductor layer, the first conductive layer, and the second conductive layer; and

a gate electrode layer provided over the oxide semiconductor layer with the gate insulating layer provided therebetween,

wherein the gate electrode layer is overlapped with the first conductive layer with the gate insulating layer provided therebetween, and is not overlapped with the second conductive layer with the gate insulating layer provided therebetween.

24. The semiconductor device according to claim 23, wherein the embedded conductive layer is in contact with the first conductive layer in an opening in the oxide semiconductor layer.

25. The semiconductor device according to claim 23, wherein the insulating layer partly comprising the embedded conductive layer comprises an embedded oxide semiconductor layer over the embedded conductive layer.

26. The semiconductor device according to claim 25, wherein the insulating layer partly comprising the embedded conductive layer and the embedded oxide semiconductor layer is provided such that the embedded oxide semiconductor layer is in contact with the first conductive layer in the opening in the oxide semiconductor layer in the semiconductor device.

27. The semiconductor device according to claim 23, wherein a thickness of the first conductive layer is greater than or equal to 5 nm and less than or equal to 20 nm.

28. The semiconductor device according to claim 23, wherein a thickness of the gate insulating layer is greater than or equal to 10 nm and less than or equal to 20 nm.

29. The semiconductor device according to claim 23, wherein a thickness of the oxide semiconductor layer is greater than or equal to 5 nm and less than or equal to 20 nm.

30. The semiconductor device according to claim 23, wherein a buffer layer is provided over the substrate comprising the insulating surface.

31. The semiconductor device according to claim 30, wherein the buffer layer comprises an oxide of at least one element selected from the group consisting of aluminum, gallium, zirconium, hafnium, and a rare-earth element.

32. The semiconductor device according to claim 23, wherein the oxide semiconductor layer comprises crystals whose c-axes are aligned.