Semiconductor device and method for manufacturing the same

• US 9,130,043 B2
• Filed: 09/29/2010
• Issued: 09/08/2015
• Est. Priority Date: 10/01/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Akimoto, Kengo
• Primary Examiner(s): Tran, Tan N
• Assistant Examiner(s): Wilson, Scott R
• Application Number:
  US12/893,513
• Publication Number:
  US 20110079777A1
• Time in Patent Office: 1,805 Days
• Field of Search: None
• US Class Current: 1/1
• 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 29/41733 for thin film transistors with insulated gate
• 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 29/78603 characterised by the insulating substrate or support H01L29/78657 takes 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

An object is to provide a method for manufacturing a highly reliable semiconductor device which includes a thin film transistor using an oxide semiconductor and having stable electric characteristics. In manufacture of a semiconductor device in which an oxide semiconductor is used for a channel formation region, after an oxide semiconductor film is formed, a conductive film including a metal, a metal compound, or an alloy that can absorb or adsorb moisture, a hydroxy group, or hydrogen is formed to overlap with the oxide semiconductor film with an insulating film provided therebetween. Then, heat treatment is performed in the state where the conductive film is exposed; in such a manner, activation treatment for removing moisture, oxygen, hydrogen, or the like adsorbed onto a surface of or in the conductive film is performed.

Claims

1. A method for manufacturing a semiconductor device, comprising the steps of:

forming a gate insulating film over a first gate electrode on an insulating surface;

forming an oxide semiconductor film over the gate insulating film;

forming a source electrode and a drain electrode over the oxide semiconductor film;

forming a first insulating film over the oxide semiconductor film, the source electrode, and the drain electrode and in contact with the oxide semiconductor film;

forming a second gate electrode over the first insulating film to overlap with a whole of the oxide semiconductor film, wherein the second gate electrode comprises a depression; and

performing heat treatment in a state where the second gate electrode is exposed, and

wherein the second gate electrode includes a hydrogen absorbing alloy.

2. The method for manufacturing a semiconductor device according to claim 1, wherein the heat treatment is performed at higher than or equal to 350°

C. and lower than or equal to 650°

C.

3. The method for manufacturing a semiconductor device according to claim 1, wherein the second gate electrode is formed using a mixture, a metal compound, or an alloy which includes one or more of titanium, platinum, vanadium, zirconium, hafnium, palladium, magnesium, niobium, or a rare earth meal.

4. The method for manufacturing a semiconductor device according to claim 1, wherein the hydrogen absorbing alloy is at least one of LaNi₅, a Ti—

Mn-based alloy, a Ti—

Cr-based alloy, a Zr—

Mn-based alloy, a Ti—

V—

Mn-based alloy, Mg₂Ni, Mg₂Cu, and Ti₂Ni.

5. The method for manufacturing a semiconductor device according to claim 1, wherein the heat treatment is performed under an inert gas atmosphere or a reduced-pressure atmosphere.

6. The method for manufacturing a semiconductor device according to claim 1, wherein the first insulating film is an oxide insulating film.

7. The method for manufacturing a semiconductor device according to claim 1, further comprising the step of forming a second insulating film over the second gate electrode after the step of performing the heat treatment.

8. The method for manufacturing a semiconductor device according to claim 1, wherein the second gate electrode absorbs moisture, a hydroxy group, or hydrogen which are present in the gate insulating film, in the oxide semiconductor film, at an interface between the gate insulating film and the oxide semiconductor film, or at an interface between the oxide semiconductor film and the first insulating film by performing the heat treatment.

9. The method for manufacturing a semiconductor device according to claim 1, further comprising the step of generating plasma in vicinity a substrate to modify a surface of the gate insulating film before the oxide semiconductor film is formed.

10. A method for manufacturing a semiconductor device, comprising the steps of:

forming a gate insulating film over a first gate electrode on an insulating surface;

forming a source electrode and a drain electrode over the gate insulating film;

forming an oxide semiconductor film over the source electrode and the drain electrode;

forming a first insulating film over the oxide semiconductor film, the source electrode, and the drain electrode and in contact with the oxide semiconductor film;

forming a second gate electrode over the first insulating film to overlap with a whole of the oxide semiconductor film, wherein the second gate electrode comprises a depression; and

performing heat treatment in a state where the second gate electrode is exposed, and

wherein the second gate electrode includes a hydrogen absorbing alloy.

11. The method for manufacturing a semiconductor device according to claim 10, wherein the heat treatment is performed at higher than or equal to 350°

C. and lower than or equal to 650°

C.

12. The method for manufacturing a semiconductor device according to claim 10, wherein the second gate electrode is formed using a mixture, a metal compound, or an alloy which includes one or more of titanium, platinum, vanadium, zirconium, hafnium, palladium, magnesium, niobium, or a rare earth meal.

13. The method for manufacturing a semiconductor device according to claim 10, wherein the hydrogen absorbing alloy is at least one of LaNi₅, a Ti—

Mn-based alloy, a Ti—

Cr-based alloy, a Zr—

Mn-based alloy, a Ti—

V—

Mn-based alloy, Mg₂Ni, Mg₂Cu, and Ti₂Ni.

14. The method for manufacturing a semiconductor device according to claim 10, wherein the heat treatment is performed under an inert gas atmosphere or a reduced-pressure atmosphere.

15. The method for manufacturing a semiconductor device according to claim 10, wherein the first insulating film is an oxide insulating film.

16. The method for manufacturing a semiconductor device according to claim 10, further comprising the step of forming a second insulating film over the second gate electrode after the step of performing the heat treatment.

17. The method for manufacturing a semiconductor device according to claim 10, wherein the second gate electrode absorbs moisture, a hydroxy group, or hydrogen which are present in the gate insulating film, in the oxide semiconductor film, at an interface between the gate insulating film and the oxide semiconductor film, or at an interface between the oxide semiconductor film and the first insulating film by performing the heat treatment.

18. The method for manufacturing a semiconductor device according to claim 10, further comprising the step of generating plasma in vicinity a substrate to modify a surface of the gate insulating film before the oxide semiconductor film is formed.

19. A method for manufacturing a semiconductor device, comprising the steps of:

forming a gate insulating film over a first gate electrode on an insulating surface;

forming an oxide semiconductor film over the gate insulating film;

forming a channel protective film over the oxide semiconductor film;

forming a source electrode and a drain electrode over the oxide semiconductor film;

forming a first insulating film over the channel protective film, the source electrode, and the drain electrode;

forming a second gate electrode over the first insulating film to overlap with a whole of the oxide semiconductor film, wherein the second gate electrode comprises a depression; and

performing heat treatment in a state where the second gate electrode is exposed, and

wherein the second gate electrode includes a hydrogen absorbing alloy.

20. The method for manufacturing a semiconductor device according to claim 19, wherein the heat treatment is performed at higher than or equal to 350°

C. and lower than or equal to 650°

C.

21. The method for manufacturing a semiconductor device according to claim 19, wherein the second gate electrode is formed using a mixture, a metal compound, or an alloy which includes one or more of titanium, platinum, vanadium, zirconium, hafnium, palladium, magnesium, niobium, or a rare earth meal.

22. The method for manufacturing a semiconductor device according to claim 19, wherein the hydrogen absorbing alloy is at least one of LaNi₅, a Ti—

Mn-based alloy, a Ti—

Cr-based alloy, a Zr—

Mn-based alloy, a Ti—

V—

Mn-based alloy, Mg₂Ni, Mg₂Cu, and Ti₂Ni.

23. The method for manufacturing a semiconductor device according to claim 19, wherein the heat treatment is performed under an inert gas atmosphere or a reduced-pressure atmosphere.

24. The method for manufacturing a semiconductor device according to claim 19, wherein the first insulating film is an oxide insulating film.

25. The method for manufacturing a semiconductor device according to claim 19, further comprising the step of forming a second insulating film over the second gate electrode after the step of performing the heat treatment.

26. The method for manufacturing a semiconductor device according to claim 19, wherein the second gate electrode absorbs moisture, a hydroxy group, or hydrogen which are present in the gate insulating film, in the oxide semiconductor film, at an interface between the gate insulating film and the oxide semiconductor film, or at an interface between the oxide semiconductor film and the first insulating film by performing the heat treatment.

27. The method for manufacturing a semiconductor device according to claim 19, further comprising the step of generating plasma in vicinity a substrate to modify a surface of the gate insulating film before the oxide semiconductor film is formed.