SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THEREOF

• US 20120153275A1
• Filed: 12/12/2011
• Published: 06/21/2012
• Est. Priority Date: 12/17/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Endo, Yuta, Sasaki, Toshinari, Noda, Kosei, Sato, Hitomi, Sato, Yuhei
• Granted Patent: US 9,202,822 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 21/28088 the final conductor layer next to the insulator being a composite, e.g. TiN
• CPC Class Codes: H01L 21/288 from a liquid, e.g. electrolytic deposition
• 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 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 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• 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

To manufacture a transistor whose threshold voltage is controlled without using a backgate electrode, a circuit for controlling the threshold voltage, and an impurity introduction method. To manufacture a semiconductor device having favorable electrical characteristics, high reliability, and low power consumption using the transistor. A gate electrode including a tungsten oxide film whose composition is controlled is used. The composition or the like is adjusted by a film formation method of the tungsten oxide film, whereby the work function can be controlled. By using the tungsten oxide film whose work function is controlled as part of the gate electrode, the threshold of the transistor can be controlled. Using the transistor whose threshold voltage is controlled, a semiconductor device having favorable electrical characteristics, high reliability, and low power consumption can be manufactured.

Claims

1. A semiconductor device comprising:

a gate electrode essentially consisting of a tungsten oxide;

a gate insulating film in contact with the gate electrode; and

a semiconductor film part of which at least overlaps with the gate electrode with the gate insulating film interposed therebetween.

2. The semiconductor device according to claim 1, further comprising a pair of electrodes between the semiconductor film and the gate insulating film.

3. The semiconductor device according to claim 1,

wherein the semiconductor film is provided over a base insulating film, and

wherein a pair of electrodes is included between the semiconductor film and the base insulating film.

4. The semiconductor device according to claim 1, further comprising:

an interlayer insulating film over the semiconductor film; and

a pair of electrodes between the semiconductor film and the interlayer insulating film.

5. The semiconductor device according to claim 1, wherein the gate electrode is formed by a sputtering method using one or more gases selected from a rare gas, oxygen, and nitrogen as a gas included in a film formation gas.

6. The semiconductor device according to claim 1, wherein the gate electrode includes nitrogen at greater than or equal to 0.1 at % and lower than or equal to 20 at %.

7. The semiconductor device according to claim 1, wherein the gate electrode is formed by performing oxidation treatment on a film including tungsten.

8. The semiconductor device according to claim 1, wherein the semiconductor film is an oxide semiconductor film.

9. The semiconductor device according to claim 8, wherein the oxide semiconductor film includes two or more elements selected from In, Ga, Zn, Sn, and Al.

10. A semiconductor device comprising:

a gate electrode including a tungsten oxide film and a film comprising any one of Al, Ti, Cr, Co, Ni, Cu, Y, Zr, Mo, Ag, and Ta;

a gate insulating film in contact with the tungsten oxide film; and

a semiconductor film part of which at least overlaps with the gate electrode with the gate insulating film interposed therebetween.

11. The semiconductor device according to claim 10, further comprising a pair of electrodes between the semiconductor film and the gate insulating film.

12. The semiconductor device according to claim 10,

wherein the semiconductor film is provided over a base insulating film, and

wherein a pair of electrodes is included between the semiconductor film and the base insulating film.

13. The semiconductor device according to claim 10, further comprising:

an interlayer insulating film over the semiconductor film; and

a pair of electrodes between the semiconductor film and the interlayer insulating film.

14. The semiconductor device according to claim 10, wherein the tungsten oxide film is formed by a sputtering method using one or more gases selected from a rare gas, oxygen, and nitrogen as a gas included in a film formation gas.

15. The semiconductor device according to claim 10, wherein the tungsten oxide film includes nitrogen at greater than or equal to 0.1 at % and lower than or equal to 20 at %.

16. The semiconductor device according to claim 10, wherein the tungsten oxide film is formed by performing oxidation treatment on a film including tungsten.

17. The semiconductor device according to claim 10, wherein the semiconductor film is an oxide semiconductor film.

18. The semiconductor device according to claim 17, wherein the oxide semiconductor film includes two or more elements selected from In, Ga, Zn, Sn, and Al.

19. A semiconductor device comprising:

a gate electrode including a tungsten oxide film;

a gate insulating film in contact with the tungsten oxide film; and

an oxide semiconductor film part of which at least overlaps with the gate electrode with the gate insulating film interposed therebetween.

20. The semiconductor device according to claim 19, further comprising a pair of electrodes between the oxide semiconductor film and the gate insulating film.

21. The semiconductor device according to claim 19,

wherein the oxide semiconductor film is provided over a base insulating film, and

wherein a pair of electrodes is included between the oxide semiconductor film and the base insulating film.

22. The semiconductor device according to claim 19, further comprising:

an interlayer insulating film over the oxide semiconductor film; and

a pair of electrodes between the oxide semiconductor film and the interlayer insulating film.

23. The semiconductor device according to claim 19, wherein the tungsten oxide film is formed by a sputtering method using one or more gases selected from a rare gas, oxygen, and nitrogen as a gas included in a film formation gas.

24. The semiconductor device according to claim 19, wherein the tungsten oxide film includes nitrogen at greater than or equal to 0.1 at % and lower than or equal to 20 at %.

25. The semiconductor device according to claim 19, wherein the tungsten oxide film is formed by performing oxidation treatment on a film including tungsten.

26. The semiconductor device according to claim 19, wherein the oxide semiconductor film includes two or more elements selected from In, Ga, Zn, Sn, and Al.

27. A method for manufacturing a semiconductor device comprising:

forming a gate electrode including a tungsten oxide film by a sputtering method over a substrate;

forming a gate insulating film over the gate electrode;

forming a semiconductor film over the gate insulating film.

28. The method according to claim 27 further comprising:

forming a pair of electrodes between the gate electrode and the semiconductor film before forming the semiconductor film.

29. The method according to claim 27 further comprising:

forming a pair of electrodes over the semiconductor film.

30. The method according to claim 27, wherein one or more gases selected from a rare gas, oxygen, and nitrogen is used as a film formation gas in the sputtering method.

31. The method according to claim 27 further comprising:

performing heat treatment after forming the gate electrode.

32. The method according to claim 27, wherein the semiconductor film is an oxide semiconductor film.

33. The method according to claim 32, wherein the oxide semiconductor film includes two or more elements selected from In, Ga, Zn, Sn, and Al.

34. The method according to claim 27, wherein the sputtering method is a bias sputtering method.

35. A method for manufacturing a semiconductor device comprising:

forming a semiconductor film over a substrate;

forming a gate insulating film over the semiconductor film;

forming a gate electrode including a tungsten oxide film by a sputtering method over the gate insulating film.

36. The method according to claim 35 further comprising:

forming a pair of electrodes between the gate electrode and the semiconductor film before forming the semiconductor film.

37. The method according to claim 35 further comprising:

forming a pair of electrodes over the semiconductor film.

38. The method according to claim 35, wherein one or more gases selected from a rare gas, oxygen, and nitrogen is used as a film formation gas in the sputtering method.

39. The method according to claim 35 further comprising:

performing heat treatment after forming the gate electrode.

40. The method according to claim 35, wherein the semiconductor film is an oxide semiconductor film.

41. The method according to claim 40, wherein the oxide semiconductor film includes two or more elements selected from In, Ga, Zn, Sn, and Al.

42. The method according to claim 35, wherein the sputtering method is a bias sputtering method.