SEMICONDUCTOR DEVICE AND MANUFACTURING METHOD THE SAME

• US 20120280230A1
• Filed: 07/19/2012
• Published: 11/08/2012
• Est. Priority Date: 10/21/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: AKIMOTO, Kengo, SAKATA, Junichiro, YAMAZAKI, Shunpei
• Granted Patent: US 8,946,700 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• 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 29/78618 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

An object is to provide a method for manufacturing a highly reliable semiconductor device including thin film transistors which have stable electric characteristics and are formed using an oxide semiconductor. A method for manufacturing a semiconductor device includes the steps of: forming an oxide semiconductor film over a gate electrode with a gate insulating film interposed between the oxide semiconductor film and the gate electrode, over an insulating surface; forming a first conductive film including at least one of titanium, molybdenum, and tungsten, over the oxide semiconductor film; forming a second conductive film including a metal having lower electronegativity than hydrogen, over the first conductive film; forming a source electrode and a drain electrode by etching of the first conductive film and the second conductive film; and forming an insulating film in contact with the oxide semiconductor film, over the oxide semiconductor film, the source electrode, and the drain electrode.

Claims

1. A semiconductor device comprising:

a gate electrode over a substrate;

a first insulating film over the gate electrode, the first insulating film comprising silicon nitride;

a second insulating film over the first insulating film, the second insulating film comprising silicon oxide;

an oxide semiconductor film over the second insulating film, the oxide semiconductor film comprising indium and oxygen;

a source electrode over the oxide semiconductor film;

a drain electrode over the oxide semiconductor film;

a third insulating film over the oxide semiconductor film, the source electrode, and the drain electrode, the third insulating film comprising silicon oxide;

a fourth insulating film over the third insulating film, the fourth insulating film comprising silicon nitride; and

a pixel electrode over the fourth insulating film, the pixel electrode electrically connected to one of the source electrode and the drain electrode,

wherein the oxide semiconductor film comprises a depressed portion between the source electrode and the drain electrode, the depressed portion overlapping with the gate electrode,

wherein the third insulating film is in contact with the depressed portion, and

wherein a whole of the oxide semiconductor film overlaps with the gate electrode.

2. The semiconductor device according to claim 1, wherein the oxide semiconductor film comprises an In—

Ga—

Zn—

O-based oxide semiconductor.

3. The semiconductor device according to claim 1, wherein the oxide semiconductor film comprises one selected from the group consisting of an In—

Sn—

Ga—

Zn—

O-based oxide semiconductor, an In—

Sn—

Zn—

O-based oxide semiconductor, an In—

Al—

Zn—

O-based oxide semiconductor, an In—

Zn—

O-based oxide semiconductor, an In—

Mg—

O-based oxide semiconductor, an In—

Ga—

O-based oxide semiconductor, and an In—

O-based oxide semiconductor.

4. The semiconductor device according to claim 1, wherein the second insulating film comprising silicon oxide is in contact with the third insulating film comprising silicon oxide.

5. The semiconductor device according to claim 1,

wherein the third insulating film extends in a direction of a channel length of the oxide semiconductor film from a first position to a third position via a second position, so as to interpose the source electrode and the drain electrode between the third insulating film and the second insulating film,

wherein the third insulating film is in contact with the second insulating film in the first position and in the third position, and the third insulating film is in contact with the oxide semiconductor film in the second position.

6. The semiconductor device according to claim 1, wherein a proportion of nitrogen included in the second insulating film is lower than a proportion of nitrogen included in the first insulating film.

7. The semiconductor device according to claim 1, wherein the oxide semiconductor film is a non-single crystal oxide semiconductor film.

8. The semiconductor device according to claim 1, wherein a carrier concentration of the oxide semiconductor film is less than 1×

10¹⁸/cm³.

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

a liquid crystal layer over the pixel electrode;

a second substrate over the liquid crystal layer; and

a spacer between the substrate and the second substrate, the spacer overlapping with the gate electrode.

10. The semiconductor device according to claim 1,

wherein each of the source electrode and the drain electrode comprises a first conductive film and a second conductive film over the first conductive film,

wherein the first conductive film comprises one selected from the group consisting of titanium, molybdenum, and tungsten, and

wherein the second conductive film comprises a metal having lower electronegativity than hydrogen.

11. The semiconductor device according to claim 1, further comprising an FPC connected to the substrate.

12. A semiconductor device comprising:

a gate electrode over a substrate;

a first insulating film over the gate electrode, the first insulating film comprising silicon nitride;

a second insulating film over the first insulating film, the second insulating film comprising silicon oxynitride;

an oxide semiconductor film over the second insulating film, the oxide semiconductor film comprising indium and oxygen;

a source electrode over the oxide semiconductor film;

a drain electrode over the oxide semiconductor film;

a third insulating film over the oxide semiconductor film, the source electrode, and the drain electrode, the third insulating film comprising silicon oxynitride;

a fourth insulating film over the third insulating film, the fourth insulating film comprising silicon nitride; and

a pixel electrode over the fourth insulating film, the pixel electrode electrically connected to one of the source electrode and the drain electrode,

wherein the oxide semiconductor film comprises a depressed portion between the source electrode and the drain electrode, the depressed portion overlapping with the gate electrode,

wherein the third insulating film is in contact with the depressed portion, and

wherein a whole of the oxide semiconductor film overlaps with the gate electrode.

13. The semiconductor device according to claim 12, wherein the oxide semiconductor film comprises an In—

Ga—

Zn—

O-based oxide semiconductor.

14. The semiconductor device according to claim 12, wherein the oxide semiconductor film comprises one selected from the group consisting of an In—

Sn—

Ga—

Zn—

O-based oxide semiconductor, an In—

Sn—

Zn—

O-based oxide semiconductor, an In—

Al—

Zn—

O-based oxide semiconductor, an In—

Zn—

O-based oxide semiconductor, an In—

Mg—

O-based oxide semiconductor, an In—

Ga—

O-based oxide semiconductor, and an In—

O-based oxide semiconductor.

15. The semiconductor device according to claim 12, wherein the second insulating film comprising silicon oxynitride is in contact with the third insulating film comprising silicon oxynitride.

16. The semiconductor device according to claim 12,

wherein the third insulating film extends in a direction of a channel length of the oxide semiconductor film from a first position to a third position via a second position, so as to interpose the source electrode and the drain electrode between the third insulating film and the second insulating film,

wherein the third insulating film is in contact with the second insulating film in the first position and in the third position, and the third insulating film is in contact with the oxide semiconductor film in the second position.

17. The semiconductor device according to claim 12, wherein a proportion of nitrogen included in the second insulating film is lower than a proportion of nitrogen included in the first insulating film.

18. The semiconductor device according to claim 12, wherein the oxide semiconductor film is a non-single crystal oxide semiconductor film.

19. The semiconductor device according to claim 12, wherein a carrier concentration of the oxide semiconductor film is less than 1×

10¹⁸/cm³.

20. The semiconductor device according to claim 12, further comprising:

a liquid crystal layer over the pixel electrode;

a second substrate over the liquid crystal layer; and

a spacer between the substrate and the second substrate, the spacer overlapping with the gate electrode.

21. The semiconductor device according to claim 12,

wherein each of the source electrode and the drain electrode comprises a first conductive film and a second conductive film over the first conductive film,

wherein the first conductive film comprises one selected from the group consisting of titanium, molybdenum, and tungsten, and

wherein the second conductive film comprises a metal having lower electronegativity than hydrogen.

22. The semiconductor device according to claim 12, further comprising an FPC connected to the substrate.

23. A semiconductor device comprising:

a gate electrode over a substrate, the gate electrode comprising copper;

a first insulating film over the gate electrode, the first insulating film comprising silicon nitride;

a second insulating film over the first insulating film, the second insulating film comprising silicon oxide;

an oxide semiconductor film over the second insulating film, the oxide semiconductor film comprising indium and oxygen;

a source electrode over the oxide semiconductor film;

a drain electrode over the oxide semiconductor film;

a third insulating film over the oxide semiconductor film, the source electrode, and the drain electrode, the third insulating film comprising silicon oxide;

a fourth insulating film over the third insulating film, the fourth insulating film comprising silicon nitride; and

a pixel electrode over the fourth insulating film, the pixel electrode electrically connected to one of the source electrode and the drain electrode,

wherein the oxide semiconductor film comprises a depressed portion between the source electrode and the drain electrode, the depressed portion overlapping with the gate electrode,

wherein the third insulating film is in contact with the depressed portion, and

wherein the second insulating film comprising silicon oxide is in contact with the third insulating film comprising silicon oxide.

24. The semiconductor device according to claim 23, wherein the oxide semiconductor film comprises an In—

Ga—

Zn—

O-based oxide semiconductor.

25. The semiconductor device according to claim 23, wherein the oxide semiconductor film comprises one selected from the group consisting of an In—

Sn—

Ga—

Zn—

O-based oxide semiconductor, an In—

Sn—

Zn—

O-based oxide semiconductor, an In—

Al—

Zn—

O-based oxide semiconductor, an In—

Zn—

O-based oxide semiconductor, an In—

Mg—

O-based oxide semiconductor, an In—

Ga—

O-based oxide semiconductor, and an In—

O-based oxide semiconductor.

26. The semiconductor device according to claim 23,

wherein the third insulating film extends in a direction of a channel length of the oxide semiconductor film from a first position to a third position via a second position, so as to interpose the source electrode and the drain electrode between the third insulating film and the second insulating film,

wherein the third insulating film is in contact with the second insulating film in the first position and in the third position, and the third insulating film is in contact with the oxide semiconductor film in the second position.

27. The semiconductor device according to claim 23, wherein a proportion of nitrogen included in the second insulating film is lower than a proportion of nitrogen included in the first insulating film.

28. The semiconductor device according to claim 23, wherein the oxide semiconductor film is a non-single crystal oxide semiconductor film.

29. The semiconductor device according to claim 23, wherein a carrier concentration of the oxide semiconductor film is less than 1×

10¹⁸/cm³.

30. The semiconductor device according to claim 23, further comprising:

a liquid crystal layer over the pixel electrode;

a second substrate over the liquid crystal layer; and

a spacer between the substrate and the second substrate, the spacer overlapping with the gate electrode.

31. The semiconductor device according to claim 23,

wherein each of the source electrode and the drain electrode comprises a first conductive film and a second conductive film over the first conductive film,

wherein the first conductive film comprises one selected from the group consisting of titanium, molybdenum, and tungsten, and

wherein the second conductive film comprises a metal having lower electronegativity than hydrogen.

32. The semiconductor device according to claim 23, further comprising an FPC connected to the substrate.

33. A semiconductor device comprising:

a gate electrode over a substrate, the gate electrode comprising copper;

a first insulating film over the gate electrode, the first insulating film comprising silicon nitride;

a second insulating film over the first insulating film, the second insulating film comprising silicon oxynitride;

an oxide semiconductor film over the second insulating film, the oxide semiconductor film comprising indium and oxygen;

a source electrode over the oxide semiconductor film;

a drain electrode over the oxide semiconductor film;

a third insulating film over the oxide semiconductor film, the source electrode, and the drain electrode, the third insulating film comprising silicon oxynitride;

a fourth insulating film over the third insulating film, the fourth insulating film comprising silicon nitride; and

a pixel electrode over the fourth insulating film, the pixel electrode electrically connected to one of the source electrode and the drain electrode,

wherein the oxide semiconductor film comprises a depressed portion between the source electrode and the drain electrode, the depressed portion overlapping with the gate electrode, and

wherein the third insulating film is in contact with the depressed portion.

34. The semiconductor device according to claim 33, wherein the oxide semiconductor film comprises an In—

Ga—

Zn—

O-based oxide semiconductor.

35. The semiconductor device according to claim 33, wherein the oxide semiconductor film comprises one selected from the group consisting of an In—

Sn—

Ga—

Zn—

O-based oxide semiconductor, an In—

Sn—

Zn—

O-based oxide semiconductor, an In—

Al—

Zn—

O-based oxide semiconductor, an In—

Zn—

O-based oxide semiconductor, an In—

Mg—

O-based oxide semiconductor, an In—

Ga—

O-based oxide semiconductor, and an In—

O-based oxide semiconductor.

36. The semiconductor device according to claim 33, wherein the second insulating film comprising silicon oxynitride is in contact with the third insulating film comprising silicon oxynitride.

37. The semiconductor device according to claim 33,

wherein the third insulating film extends in a direction of a channel length of the oxide semiconductor film from a first position to a third position via a second position, so as to interpose the source electrode and the drain electrode between the third insulating film and the second insulating film,

wherein the third insulating film is in contact with the second insulating film in the first position and in the third position, and the third insulating film is in contact with the oxide semiconductor film in the second position.

38. The semiconductor device according to claim 33, wherein a proportion of nitrogen included in the second insulating film is lower than a proportion of nitrogen included in the first insulating film.

39. The semiconductor device according to claim 33, wherein the oxide semiconductor film is a non-single crystal oxide semiconductor film.

40. The semiconductor device according to claim 33, wherein a carrier concentration of the oxide semiconductor film is less than 1×

10¹⁸/cm³.

41. The semiconductor device according to claim 33, further comprising:

a liquid crystal layer over the pixel electrode;

a second substrate over the liquid crystal layer; and

a spacer between the substrate and the second substrate, the spacer overlapping with the gate electrode.

42. The semiconductor device according to claim 33,

wherein each of the source electrode and the drain electrode comprises a first conductive film and a second conductive film over the first conductive film,

wherein the first conductive film comprises one selected from the group consisting of titanium, molybdenum, and tungsten, and

wherein the second conductive film comprises a metal having lower electronegativity than hydrogen.

43. The semiconductor device according to claim 33, further comprising an FPC connected to the substrate.