Semiconductor device

• US 8,530,944 B2
• Filed: 03/01/2011
• Issued: 09/10/2013
• Est. Priority Date: 03/08/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Lam, Cathy N
• Application Number:
  US13/037,686
• Publication Number:
  US 20110215385A1
• Time in Patent Office: 924 Days
• Field of Search: 257/288, 257/E29.255, 257/59, 257/57, 257/E21.15, 257/66, 257/43, 257/775, 257/40, 438/34, 438/104, 438/706, 438/59
• US Class Current: 257/288
• CPC Class Codes: H01L 27/1225 with semiconductor materials not belonging to the group IV of the periodic table, e.g. InGaZnO
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 29/41733 for thin film transistors with insulated gate
• CPC Class Codes: H01L 29/45 Ohmic electrodes
• CPC Class Codes: H01L 29/66969 of devices having semiconductor bodies not comprising group 14 or group 13/15 materials comprising selenium or tellurium in uncombined form other than as impurities in semiconductor bodies of other materials, comprising cuprous oxide or cuprous iodide H01L21/02365
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate
• CPC Class Codes: H10B 41/30 characterised by the memory core region
• CPC Class Codes: H10B 41/35 with a cell select transistor, e.g. NAND
• CPC Class Codes: H10B 41/70 the floating gate being an electrode shared by two or more components

Abstract

An object is to provide a semiconductor device which achieves miniaturization as well as suppressing a defect. Further, another object is to provide a semiconductor device which achieves miniaturization as well as keeping favorable characteristics. Is provided a semiconductor device including: a source wiring and a drain wiring each of which include a first conductive layer and a second conductive layer having a smaller thickness than the first conductive layer; an insulating layer which has an opening portion and is provided over the source wiring and the drain wiring; an oxide semiconductor layer which is in contact with part of the second conductive layer of the source wiring or the drain wiring in the opening portion; a gate insulating layer provided over the oxide semiconductor layer; and a gate electrode provided over the gate insulating layer.

Claims

1. A semiconductor device comprising:

a wiring which includes a first conductive layer and a second conductive layer having a smaller thickness than the first conductive layer;

an insulating layer having an opening portion over the wiring;

a semiconductor layer over the insulating layer;

a gate insulating layer over the semiconductor layer; and

a gate electrode over the gate insulating layer,

wherein the semiconductor layer is in contact with a part of the wiring through the opening portion in a region comprising a single layer of the second conductive layer in the wiring.

2. The semiconductor device according to claim 1, wherein the second conductive layer has a larger length in a channel length direction than the first conductive layer.

3. The semiconductor device according to claim 1, wherein a material of the second conductive layer is a metal material having higher work function than a material of the semiconductor layer.

4. The semiconductor device according to claim 1, wherein the region, in the wiring, which is led for connection with an external circuit is a region comprising a single layer of the first conductive layer or a region comprising a stacked layer of the first conductive layer and the second conductive layer.

5. The semiconductor device according to claim 1, wherein the region comprising the single layer of the second conductive layer in the wiring includes the second conductive layer extended beyond an edge portion of the first conductive layer in a channel width direction.

6. The semiconductor device according to claim 1, wherein the second conductive layer is on and in direct contact with the first conductive layer.

7. The semiconductor device according to claim 1, wherein the first conductive layer comprising a material with higher conductivity than a material of the second conductive layer.

8. The semiconductor device according to claim 1, wherein the wiring is a drain wiring.

9. A semiconductor device comprising:

a source wiring and a drain wiring each of which includes a first conductive layer and a second conductive layer having a smaller thickness than the first conductive layer;

an insulating layer having an opening portion over the source wiring and the drain wiring;

a semiconductor layer over the insulating layer;

a gate insulating layer over the semiconductor layer; and

a gate electrode over the gate insulating layer,

wherein the semiconductor layer is in contact with a part of the source wiring or the drain wiring through the opening portion in a region comprising a single layer of the second conductive layer in the source wiring or the drain wiring, and

wherein the semiconductor layer is an oxide semiconductor layer.

10. The semiconductor device according to claim 9, wherein the second conductive layer has a larger length in a channel length direction than the first conductive layer.

11. The semiconductor device according to claim 9, wherein a material of the second conductive layer is a metal material having higher work function than a material of the semiconductor layer.

12. The semiconductor device according to claim 9, wherein the region, in each of the source wiring and the drain wiring, which is led for connection with an external circuit is a region comprising a single layer of the first conductive layer or a region comprising a stacked layer of the first conductive layer and the second conductive layer.

13. The semiconductor device according to claim 9, wherein the region comprising the single layer of the second conductive layer in the source wiring or the drain wiring includes the second conductive layer extended beyond an edge portion of the first conductive layer in a channel width direction.

14. The semiconductor device according to claim 9, wherein the second conductive layer is on and in direct contact with the first conductive layer.

15. The semiconductor device according to claim 9, wherein the first conductive layer comprising a material with higher conductivity than a material of the second conductive layer.

16. A semiconductor device comprising:

a source wiring and a drain wiring each of which includes a first conductive layer and a second conductive layer having a smaller thickness than the first conductive layer;

an insulating layer having an opening portion over the source wiring and the drain wiring;

a semiconductor layer over the insulating layer;

a gate insulating layer over the semiconductor layer; and

a gate electrode over the gate insulating layer,

wherein the semiconductor layer is in contact with a part of the source wiring or the drain wiring through the opening portion in a region comprising a single layer of the second conductive layer in the source wiring or the drain wiring,

wherein the semiconductor layer is an oxide semiconductor layer, and

wherein the insulating layer is provided so as to fill a space between the source wiring and the drain wiring.

17. The semiconductor device according to claim 16, wherein the second conductive layer has a larger length in a channel length direction than the first conductive layer.

18. The semiconductor device according to claim 16, wherein a material of the second conductive layer is a metal material having higher work function than a material of the semiconductor layer.

19. The semiconductor device according to claim 16, wherein the region, in each of the source wiring and the drain wiring, which is led for connection with an external circuit is a region comprising a single layer of the first conductive layer or a region comprising a stacked layer of the first conductive layer and the second conductive layer.

20. The semiconductor device according to claim 16, wherein the region comprising the single layer of the second conductive layer in the source wiring or the drain wiring includes the second conductive layer extended beyond an edge portion of the first conductive layer in a channel width direction.

21. The semiconductor device according to claim 16, wherein the second conductive layer is on and in direct contact with the first conductive layer.

22. The semiconductor device according to claim 16, wherein the first conductive layer comprising a material with higher conductivity than a material of the second conductive layer.