Semiconductor device and method for manufacturing the same

• US 9,728,555 B2
• Filed: 10/29/2015
• Issued: 08/08/2017
• Est. Priority Date: 02/05/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Ha, Nathan W
• Application Number:
  US14/926,722
• Publication Number:
  US 20160071889A1
• Time in Patent Office: 649 Days
• Field of Search: 257 59
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• 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 27/1266 the substrate on which the devices are formed not being the final device substrate, e.g. using a temporary substrate
• CPC Class Codes: H01L 29/1033 with insulated gate, e.g. characterised by the length, the width, the geometric contour or the doping structure with channel and gate aligned in the lengthwise direction H01L29/42376; with buried channel H01L29/7838
• CPC Class Codes: H01L 29/24 including, apart from doping materials or other impurities, only semiconductor materials not provided for in groups H01L29/16, H01L29/18, H01L29/20, H01L29/22 including organic materials H10K99/00
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• 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 29/78606 with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device H01L29/78642, H01L29/78645 take precedence
• 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 more convenient and highly reliable semiconductor device which has a transistor including an oxide semiconductor with higher impact resistance used for a variety of applications is provided. A semiconductor device has a bottom-gate transistor including a gate electrode layer, a gate insulating layer, and an oxide semiconductor layer over a substrate, an insulating layer over the transistor, and a conductive layer over the insulating layer. The insulating layer covers the oxide semiconductor layer and is in contact with the gate insulating layer. In a channel width direction of the oxide semiconductor layer, end portions of the gate insulating layer and the insulating layer are aligned with each other over the gate electrode layer, and the conductive layer covers a channel formation region of the oxide semiconductor layer and the end portions of the gate insulating layer and the insulating layer and is in contact with the gate electrode layer.

Claims

1. A semiconductor device comprising a transistor, the transistor comprising:

a first conductive layer;

a first insulating layer over the first conductive layer;

an oxide semiconductor layer over the first insulating layer;

a second insulating layer over the oxide semiconductor layer; and

a second conductive layer over the second insulating layer,

wherein the oxide semiconductor layer overlaps with the first conductive layer and the second conductive layer,

wherein each of the first conductive layer and the second conductive layer extends beyond both side edges of the oxide semiconductor layer in a channel width direction of the transistor,

wherein the oxide semiconductor layer is surrounded by the first insulating layer and the second insulating layer, and

wherein a channel width of the transistor is larger than a channel length of the transistor.

2. The semiconductor device according to claim 1, wherein the semiconductor device is a display device.

3. The semiconductor device according to claim 1, wherein the transistor is included in a driver circuit.

4. The semiconductor device according to claim 1, wherein a carrier concentration of a channel formation region of the transistor is lower than 1×

10¹¹/cm³.

5. The semiconductor device according to claim 1, wherein the transistor comprises:

a source electrode over and electrically connected with the oxide semiconductor layer; and

a drain electrode over and electrically connected with the oxide semiconductor layer.

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

7. A semiconductor device comprising a transistor, the transistor comprising:

a first conductive layer;

a first insulating layer over the first conductive layer;

an oxide semiconductor layer formed over the first insulating layer in a state where a substrate over which the first conductive layer is formed is heated;

a second insulating layer over the oxide semiconductor layer; and

a second conductive layer over the second insulating layer,

wherein the oxide semiconductor layer overlaps with the first conductive layer and the second conductive layer,

wherein each of the first conductive layer and the second conductive layer extends beyond both side edges of the oxide semiconductor layer in a channel width direction of the transistor,

wherein the oxide semiconductor layer is surrounded by the first insulating layer and the second insulating layer,

wherein a channel width of the transistor is larger than a channel length of the transistor, and

wherein the oxide semiconductor layer is dehydrated or dehydrogenated and then oxygen is supplied to the oxide semiconductor layer.

8. The semiconductor device according to claim 7, wherein the semiconductor device is a display device.

9. The semiconductor device according to claim 7, wherein the transistor is included in a driver circuit.

10. The semiconductor device according to claim 7, wherein a carrier concentration of a channel formation region of the transistor is lower than 1×

10¹¹/cm³.

11. The semiconductor device according to claim 7, wherein the transistor comprises:

a source electrode over and electrically connected with the oxide semiconductor layer; and

a drain electrode over and electrically connected with the oxide semiconductor layer.

12. The semiconductor device according to claim 7, wherein the second conductive layer is in contact with and electrically connected to the first conductive layer.

13. A semiconductor device comprising a transistor, the transistor comprising:

a first conductive layer;

a first insulating layer;

an oxide semiconductor layer over the first insulating layer; and

a second insulating layer over the oxide semiconductor layer,

wherein the oxide semiconductor layer overlaps with the first conductive layer,

wherein the first conductive layer extends beyond both side edges of the oxide semiconductor layer in a channel width direction of the transistor,

wherein the oxide semiconductor layer is surrounded by the first insulating layer and the second insulating layer, and

wherein a channel width of the transistor is larger than a channel length of the transistor.

14. The semiconductor device according to claim 13,

wherein the first conductive layer comprises a first region overlapping with the oxide semiconductor layer and a second region not overlapping with the oxide semiconductor layer, and

wherein a length of the second region in a direction perpendicular to an extending direction of the first conductive layer is longer than a length of the first region in a direction perpendicular to the extending direction of the first conductive layer.

15. The semiconductor device according to claim 14, wherein the semiconductor device is a display device.

16. The semiconductor device according to claim 14, wherein the transistor is included in a driver circuit.

17. The semiconductor device according to claim 14, wherein a carrier concentration of a channel formation region of the transistor is lower than 1×

10¹¹/cm³.

18. The semiconductor device according to claim 14, wherein the transistor comprises:

a source electrode over and electrically connected with the oxide semiconductor layer; and

a drain electrode over and electrically connected with the oxide semiconductor layer.

19. The semiconductor device according to claim 14, further comprising a second conductive layer in contact with and electrically connected to the first conductive layer.

20. The semiconductor device according to claim 14, wherein the first conductive layer is located under the oxide semiconductor layer.

21. A semiconductor device comprising a transistor, the transistor comprising:

a first conductive layer;

a first insulating layer;

an oxide semiconductor layer over the first insulating layer; and

a second insulating layer over the oxide semiconductor layer,

wherein the oxide semiconductor layer overlaps with the first conductive layer,

wherein the first conductive layer extends beyond both side edges of the oxide semiconductor layer in a channel width direction of the transistor,

wherein the first conductive layer comprises a first region, a second region adjacent to the first region, and a third region adjacent to the second region, the second region being interposed between the first region and the third region,

wherein the first region does not overlap with the oxide semiconductor layer, the second region overlaps with the oxide semiconductor layer, and the third region does not overlap with the oxide semiconductor layer, and

wherein a length of the second region in a direction perpendicular to an extending direction of the first conductive layer is shorter than a length of the first region in a direction perpendicular to the extending direction of the first conductive layer and shorter than a length of the third region in a direction perpendicular to the extending direction of the first conductive layer.

22. The semiconductor device according to claim 21, wherein the semiconductor device is a display device.

23. The semiconductor device according to claim 21, wherein the transistor is included in a driver circuit.

24. The semiconductor device according to claim 21, wherein a carrier concentration of a channel formation region of the transistor is lower than 1×

10¹¹/cm³.

25. The semiconductor device according to claim 21, wherein the transistor comprises:

a source electrode over and electrically connected with the oxide semiconductor layer; and

a drain electrode over and electrically connected with the oxide semiconductor layer.

26. The semiconductor device according to claim 21, further comprising a second conductive layer in contact with and electrically connected to the first conductive layer.

27. The semiconductor device according to claim 21, wherein the first conductive layer is located under the oxide semiconductor layer.

28. The semiconductor device according to claim 21, wherein a channel width of the transistor is larger than a channel length of the transistor.

29. A semiconductor device comprising a pixel portion,

wherein the pixel portion comprises a transistor, and the transistor comprises:

a first conductive layer;

a first insulating layer over the first conductive layer;

an oxide semiconductor layer over the first insulating layer; and

a second insulating layer over the oxide semiconductor layer,

wherein the oxide semiconductor layer overlaps with the first conductive layer,

wherein the first conductive layer extends beyond both side edges of the oxide semiconductor layer in a channel width direction of the transistor, and

wherein the oxide semiconductor layer comprises a crystal region which is c-axis-aligned perpendicularly to a surface of the oxide semiconductor layer.

30. The semiconductor device according to claim 29, wherein the transistor comprises:

a source electrode in contact with a top surface of the oxide semiconductor layer and a side surface of the oxide semiconductor layer;

a drain electrode in contact with a top surface of the oxide semiconductor layer and a side surface of the oxide semiconductor layer; and

a second conductive layer over the second insulating layer.

31. The semiconductor device according to claim 29, wherein a channel width of the transistor is larger than a channel length of the transistor.

32. The semiconductor device according to claim 29,

wherein the first conductive layer comprises a first region, a second region adjacent to the first region, and a third region adjacent to the second region, the second region being interposed between the first region and the third region,

wherein the first region does not overlap with the oxide semiconductor layer, the second region overlaps with the oxide semiconductor layer, and the third region does not overlap with the oxide semiconductor layer, and

wherein a length of the second region in a direction perpendicular to an extending direction of the first conductive layer is shorter than a length of the first region in a direction perpendicular to the extending direction of the first conductive layer and shorter than a length of the third region in a direction perpendicular to the extending direction of the first conductive layer.

33. A semiconductor device comprising a pixel portion,

wherein the pixel portion comprises a transistor, and the transistor comprises:

a first conductive layer;

a first insulating layer over the first conductive layer;

an oxide semiconductor layer over the first insulating layer;

a source electrode in contact with a top surface of the oxide semiconductor layer and a side surface of the oxide semiconductor layer;

a drain electrode in contact with a top surface of the oxide semiconductor layer and a side surface of the oxide semiconductor layer; and

a second insulating layer over the oxide semiconductor layer, the source electrode, and the drain electrode,

wherein the oxide semiconductor layer overlaps with the first conductive layer,

wherein the first conductive layer extends beyond both side edges of the oxide semiconductor layer in a channel width direction of the transistor,

wherein the second insulating layer is in contact with a top surface of the oxide semiconductor layer,

wherein the oxide semiconductor layer comprises a crystal region which is c-axis-aligned perpendicularly to a surface of the oxide semiconductor layer, and

wherein one of the source electrode and the drain electrode comprises a film comprising a metal having higher melting point than copper, and a copper film over the film.

34. The semiconductor device according to claim 33, wherein the oxide semiconductor layer comprises a first oxide semiconductor film and a second oxide semiconductor film over the first oxide semiconductor film.

35. The semiconductor device according to claim 33, wherein a channel width of the transistor is larger than a channel length of the transistor.

36. The semiconductor device according to claim 33,

wherein the first conductive layer comprises a first region, a second region adjacent to the first region, and a third region adjacent to the second region, the second region being interposed between the first region and the third region,

wherein the first region does not overlap with the oxide semiconductor layer, the second region overlaps with the oxide semiconductor layer, and the third region does not overlap with the oxide semiconductor layer, and

wherein a length of the second region in a direction perpendicular to an extending direction of the first conductive layer is shorter than a length of the first region in a direction perpendicular to the extending direction of the first conductive layer and shorter than a length of the third region in a direction perpendicular to the extending direction of the first conductive layer.