Semiconductor device

• US 9,865,744 B2
• Filed: 09/09/2015
• Issued: 01/09/2018
• Est. Priority Date: 01/22/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Koyama, Jun
• Primary Examiner(s): Ha, Nathan W
• Application Number:
  US14/848,486
• Publication Number:
  US 20160005874A1
• Time in Patent Office: 853 Days
• Field of Search: 257 59
• 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 27/1255 integrated with passive devices, e.g. auxiliary capacitors
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/0657 characterised by the shape of the body
• 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 29/45 Ohmic electrodes
• CPC Class Codes: H01L 29/78645 with multiple gate
• 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: H03K 17/0822 in field-effect transistor switches

Abstract

The semiconductor device includes a power element which is in an on state when voltage is not applied to a gate, a switching field-effect transistor for applying first voltage to the gate of the power element, and a switching field-effect transistor for applying voltage lower than the first voltage to the gate of the power element. The switching field-effect transistors have small off-state current.

Claims

1. A semiconductor device comprising:

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 over and electrically connected to the oxide semiconductor layer;

a drain electrode over and electrically connected to the oxide semiconductor 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 comprises;

a first region that is in contact with one of the source electrode and the drain electrode and overlaps with the first conductive layer and the second conductive layer;

a second region that is not in contact with any of the source electrode and the drain electrode and overlaps with the first conductive layer and the second conductive layer;

a third region that is not in contact with any of the source electrode and the drain electrode, overlaps with the first conductive layer, and does not overlap with the second conductive layer; and

a fourth region that is in contact with the other of the source electrode and the drain electrode, overlaps with the first conductive layer, and does not overlap with the second conductive layer,

wherein an end portion of the second conductive layer overlaps with the one of the source electrode and the drain electrode, and

wherein the source electrode and the drain electrode are each in contact with a side surface of the oxide semiconductor layer.

2. The semiconductor device according to claim 1, wherein the second conductive layer is not in contact with the source electrode and the drain electrode.

3. The semiconductor device according to claim 1, wherein the first insulating layer comprises oxygen.

4. The semiconductor device according to claim 1, wherein the oxide semiconductor layer comprises In, Zn, and one of Ga, Al, and B.

5. The semiconductor device according to claim 1,

wherein the oxide semiconductor layer comprises a crystal, and

wherein a c-axis of the crystal is along a direction perpendicular to a surface of the oxide semiconductor layer.

6. The semiconductor device according to claim 1, wherein the oxide semiconductor layer comprises a region in which a carrier density is larger than or equal to 1×

10¹⁶ cm<sup>−

3</sup> and smaller than or equal to 1×

10²⁰ cm<sup>−

3</sup>.

7. The semiconductor device according to claim 1, wherein the oxide semiconductor layer comprises a region in which a hydrogen concentration is larger than or equal to 1×

10¹⁶ cm<sup>−

3</sup> and smaller than or equal to 1×

10²⁰ cm<sup>−

3</sup>.

8. The semiconductor device according to claim 1, wherein the source electrode and the drain electrode each comprise an alloy comprising Cu and Mn.

9. The semiconductor device according to claim 1, comprising a transistor comprises the first conductive layer, the first insulating layer, the oxide semiconductor layer, the source electrode, the drain electrode, the second insulating layer, and the second conductive layer, wherein the transistor is a power metal oxide semiconductor field-effect transistor (power MOSFET).

18. The semiconductor device according to claim 1, wherein the third region is located between the first region and the fourth region.

10. A semiconductor device comprising:

a transistor comprising;

an oxide semiconductor layer;

a source electrode over the oxide semiconductor layer;

a drain electrode over the oxide semiconductor layer;

a gate insulating layer over the oxide semiconductor layer; and

a gate electrode over the gate insulating layer,

wherein the oxide semiconductor layer comprises a portion not overlapping with any of the source electrode, the drain electrode, and the gate electrode,

wherein the portion is positioned between the source electrode and the drain electrode, and

wherein the source electrode and the drain electrode are each in contact with a side surface of the oxide semiconductor layer.

11. The semiconductor device according to claim 10, wherein the oxide semiconductor layer comprises In, Ga, and Zn.

12. The semiconductor device according to claim 10, wherein the gate electrode overlaps with one of part of the source electrode and part of the drain electrode.

13. The semiconductor device according to claim 10,

wherein the oxide semiconductor layer comprises a crystal, and

wherein a c-axis of the crystal is along a direction perpendicular to a surface of the oxide semiconductor layer.

14. The semiconductor device according to claim 10, wherein the oxide semiconductor layer comprises a region in which a carrier density is larger than or equal to 1×

10¹⁶ cm<sup>−

3</sup> and smaller than or equal to 1×

10²⁰ cm<sup>−

3</sup>.

15. The semiconductor device according to claim 10, wherein the oxide semiconductor layer comprises a region in which a hydrogen concentration is larger than or equal to 1×

10¹⁶ cm<sup>−

3</sup> and smaller than or equal to 1×

10²⁰ cm<sup>−

3</sup>.

16. The semiconductor device according to claim 10, wherein the gate insulating layer is over the source electrode and the drain electrode.

17. The semiconductor device according to claim 10, wherein the transistor is a power metal oxide semiconductor field-effect transistor (power MOSFET).

19. A semiconductor device comprising:

a transistor comprising;

a first gate electrode;

a first gate insulating layer over the first gate electrode;

an oxide semiconductor layer over the first gate insulating layer;

a source electrode over the oxide semiconductor layer;

a drain electrode over the oxide semiconductor layer;

a second gate insulating layer over the oxide semiconductor layer; and

a second gate electrode over the second gate insulating layer,

wherein the oxide semiconductor layer comprises a portion not overlapping with any of the source electrode, the drain electrode, and the second gate electrode,

wherein the portion is positioned between the source electrode and the drain electrode, and

wherein the source electrode and the drain electrode are each in contact with a side surface of the oxide semiconductor layer.

20. The semiconductor device according to claim 19, wherein the oxide semiconductor layer comprises In, Ga, and Zn.

21. The semiconductor device according to claim 19, wherein the first gate electrode overlaps with one of part of the source electrode and part of the drain electrode.

22. The semiconductor device according to claim 19, wherein the second gate electrode overlaps with one of part of the source electrode and part of the drain electrode.

23. The semiconductor device according to claim 19, wherein the first gate electrode and the second gate electrode overlap with one of part of the source electrode and part of the drain electrode.

24. The semiconductor device according to claim 19,

wherein the oxide semiconductor layer comprises a crystal, and

wherein a c-axis of the crystal is along a direction perpendicular to a surface of the oxide semiconductor layer.

25. The semiconductor device according to claim 19, wherein the oxide semiconductor layer comprises a region in which a carrier density is larger than or equal to 1×

10¹⁶ cm<sup>−

3</sup> and smaller than or equal to 1×

10²⁰ cm<sup>−

3</sup>.

26. The semiconductor device according to claim 19, wherein the oxide semiconductor layer comprises a region in which a hydrogen concentration is larger than or equal to 1×

10¹⁶ cm<sup>−

3</sup> and smaller than or equal to 1×

10²⁰ cm<sup>−

3</sup>.

27. The semiconductor device according to claim 19, wherein the second gate insulating layer is over the source electrode and the drain electrode.

28. The semiconductor device according to claim 19, wherein the portion of the oxide semiconductor layer overlaps with the first gate electrode.

29. The semiconductor device according to claim 19, wherein the portion of the oxide semiconductor layer does not overlap with the first gate electrode.

30. The semiconductor device according to claim 19, wherein the first gate insulating layer and the second gate insulating layer are partly in contact with each other.

31. The semiconductor device according to claim 19, wherein the transistor is a power metal oxide semiconductor field-effect transistor (power MOSFET).

32. A semiconductor device 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 conductive layer over and electrically connected to the oxide semiconductor layer;

a third conductive layer over and electrically connected to the oxide semiconductor layer;

a second insulating layer over the oxide semiconductor layer; and

a fourth conductive layer over the second insulating layer,

wherein the oxide semiconductor layer comprises;

a first region that is in contact with the second conductive layer and overlaps with the first conductive layer and the fourth conductive layer;

a second region that is not in contact with any of the second conductive layer and the third conductive layer and overlaps with the first conductive layer and the fourth conductive layer;

a third region that is not in contact with any of the second conductive layer and the third conductive layer, overlaps with the first conductive layer, and does not overlap with the fourth conductive layer; and

a fourth region that is in contact with the third conductive layer, overlaps with the first conductive layer, and does not overlap with the fourth conductive layer,

wherein an end portion of the fourth conductive layer overlaps with the second conductive layer,

wherein the second conductive layer and the third conductive layer are each in contact with a side surface of the oxide semiconductor layer.

33. The semiconductor device according to claim 32, wherein the fourth conductive layer is not in contact with the second conductive layer and the third conductive layer.

34. The semiconductor device according to claim 32, wherein the first insulating layer comprises oxygen.

35. The semiconductor device according to claim 32, wherein the oxide semiconductor layer comprises In, Zn, and one of Ga, Al, and B.

36. The semiconductor device according to claim 32,

wherein the oxide semiconductor layer comprises a crystal, and

wherein a c-axis of the crystal is along a direction perpendicular to a surface of the oxide semiconductor layer.

37. The semiconductor device according to claim 32, wherein the oxide semiconductor layer comprises a region in which a carrier density is larger than or equal to 1×

10¹⁶ cm<sup>−

3</sup> and smaller than or equal to 1×

10²⁰ cm<sup>−

3</sup>.

38. The semiconductor device according to claim 32, wherein the oxide semiconductor layer comprises a region in which a hydrogen concentration is larger than or equal to 1×

10¹⁶ cm<sup>−

3</sup> and smaller than or equal to 1×

10²⁰ cm<sup>−

3</sup>.

39. The semiconductor device according to claim 32, wherein the second conductive layer and the third conductive layer each comprise an alloy comprising Cu and Mn.

40. The semiconductor device according to claim 32, comprising a transistor comprises the first conductive layer, the first insulating layer, the oxide semiconductor layer, the second conductive layer, the third conductive layer, the second insulating layer, and the fourth conductive layer, wherein the transistor is a power metal oxide semiconductor field-effect transistor (power MOSFET).

41. The semiconductor device according to claim 32, wherein the third region is located between the first region and the fourth region.