Method for manufacturing semiconductor device

• US 9,425,295 B2
• Filed: 04/20/2015
• Issued: 08/23/2016
• Est. Priority Date: 03/26/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): YUSHIN, NIKOLAY K
• Application Number:
  US14/690,533
• Publication Number:
  US 20150303286A1
• Time in Patent Office: 491 Days
• US Class Current: 1/1
• 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 29/42356 Disposition, e.g. buried gate electrode H01L29/42324 and H01L29/4234 take precedence
• 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
• CPC Class Codes: H01L 29/78693 the semiconducting oxide being amorphous

Abstract

In a transistor including an oxide semiconductor film, a metal oxide film which has a function of preventing electrification and covers a source electrode and a drain electrode is formed in contact with the oxide semiconductor film, and then, heat treatment is performed. Through the heat treatment, impurities such as hydrogen, moisture, a hydroxyl group, or hydride are intentionally removed from the oxide semiconductor film, whereby the oxide semiconductor film is highly purified. By providing the metal oxide film, generation of a parasitic channel on the back channel side of the oxide semiconductor film in the transistor is prevented.

Claims

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

forming a gate electrode;

forming a gate insulating film;

forming an oxide semiconductor film;

performing a first heat treatment after forming the oxide semiconductor film;

forming a source electrode and a drain electrode electrically connected to the oxide semiconductor film;

forming a metal oxide film over and in contact with the oxide semiconductor film; and

performing a second heat treatment after forming the metal oxide film,

wherein the oxide semiconductor film and the gate electrode overlap with each other with the gate insulating film interposed therebetween, and

wherein the metal oxide film comprises gallium.

2. The method for manufacturing a semiconductor device, according to claim 1, wherein the metal oxide film further comprises indium or zinc.

3. The method for manufacturing a semiconductor device, according to claim 2, wherein the metal oxide film contains indium or zinc at 0.01 at. % to 5 at. %.

4. The method for manufacturing a semiconductor device, according to claim 1, wherein each of the first heat treatment and the second heat treatment is performed at temperature of 250°

C. to 600°

C. inclusive.

5. The method for manufacturing a semiconductor device, according to claim 1, wherein a difference between a band gap of the metal oxide film and a band gap of the oxide semiconductor film is less than 3.0 eV.

6. The method for manufacturing a semiconductor device, according to claim 1, wherein hydrogen content of the metal oxide film is less than or equal to hydrogen content of the oxide semiconductor film.

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

forming a gate electrode;

forming a gate insulating film;

forming an oxide semiconductor film comprising indium and gallium;

performing a first heat treatment after forming the oxide semiconductor film;

forming a source electrode and a drain electrode electrically connected to the oxide semiconductor film;

forming a metal oxide film over and in contact with the oxide semiconductor film; and

performing a second heat treatment after forming the metal oxide film,

wherein the oxide semiconductor film and the gate electrode overlap with each other with the gate insulating film interposed therebetween,

wherein the first heat treatment is performed before forming the metal oxide film, and

wherein the metal oxide film comprises gallium.

8. The method for manufacturing a semiconductor device, according to claim 7, wherein hydrogen content of the oxide semiconductor film is reduced by the first heat treatment.

9. The method for manufacturing a semiconductor device, according to claim 7, further comprising the step of:

supplying oxygen to the oxide semiconductor film in an atmosphere containing oxygen after the first heat treatment,

wherein the first heat treatment is performed in an inert atmosphere.

10. The method for manufacturing a semiconductor device, according to claim 7, wherein the metal oxide film further comprises indium or zinc.

11. The method for manufacturing a semiconductor device, according to claim 10, wherein the metal oxide film contains indium or zinc at 0.01 at. % to 5 at. %.

12. The method for manufacturing a semiconductor device, according to claim 7, wherein each of the first heat treatment and the second heat treatment is performed at temperature of 250°

C. to 600°

C. inclusive.

13. The method for manufacturing a semiconductor device, according to claim 7, wherein a difference between a band gap of the metal oxide film and a band gap of the oxide semiconductor film is less than 3.0 eV.

14. The method for manufacturing a semiconductor device, according to claim 7, wherein hydrogen content of the metal oxide film is less than or equal to hydrogen content of the oxide semiconductor film.

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

forming a gate electrode;

forming a gate insulating film;

forming an oxide semiconductor film comprising indium and gallium;

forming a source electrode and a drain electrode electrically connected to the oxide semiconductor film;

forming a metal oxide film over and in contact with the oxide semiconductor film; and

supplying oxygen to the oxide semiconductor film from the metal oxide film by performing a heat treatment,

wherein the oxide semiconductor film and the gate electrode overlap with each other with the gate insulating film interposed therebetween, and

wherein the metal oxide film comprises gallium.

16. The method for manufacturing a semiconductor device, according to claim 15, further comprising the step of:

performing a heat treatment on the oxide semiconductor film before forming the metal oxide film,

wherein hydrogen content of the oxide semiconductor film is reduced by the heat treatment on the oxide semiconductor film.

17. The method for manufacturing a semiconductor device, according to claim 15, wherein the oxide semiconductor film becomes an intrinsic oxide semiconductor film after the heat treatment.

18. The method for manufacturing a semiconductor device, according to claim 15,

wherein carrier concentration of the oxide semiconductor film after the heat treatment is less than 1×

10¹⁴/cm³.

19. The method for manufacturing a semiconductor device, according to claim 15, wherein the metal oxide film further comprises indium or zinc.

20. The method for manufacturing a semiconductor device, according to claim 19, wherein the metal oxide film contains indium or zinc at 0.01 at. % to 5 at. %.

21. The method for manufacturing a semiconductor device, according to claim 15, wherein the heat treatment is performed at temperature of 250°

C. to 600°

C. inclusive.

22. The method for manufacturing a semiconductor device, according to claim 15, wherein a difference between a band gap of the metal oxide film and a band gap of the oxide semiconductor film is less than 3.0 eV.

23. The method for manufacturing a semiconductor device, according to claim 15, wherein hydrogen content of the metal oxide film is less than or equal to hydrogen content of the oxide semiconductor film.