SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

• US 20120132903A1
• Filed: 11/16/2011
• Published: 05/31/2012
• Est. Priority Date: 11/30/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: YAMAZAKI, Shunpei, TAKAHASHI, Masahiro, MARUYAMA, Tetsunori
• Granted Patent: US 8,728,883 B2
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: H01L 21/0242 Crystalline insulating materials
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02472 Oxides
• CPC Class Codes: H01L 21/02483 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02502 consisting of two layers
• CPC Class Codes: H01L 21/02513 Microstructure
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/0259 Microstructure
• CPC Class Codes: H01L 29/06 characterised by their shape; characterised by the shapes, relative sizes, or dispositions of the semiconductor regions ; characterised by the concentration or distribution of impurities within semiconductor regions
• CPC Class Codes: H01L 29/36 characterised by the concentration or distribution of impurities in the bulk material within semiconductor regions H01L29/06
• 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 29/7869 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

A highly reliable semiconductor device is manufactured by giving stable electric characteristics to a transistor in which an oxide semiconductor film is used for a channel. An oxide semiconductor film which can have a first crystal structure by heat treatment and an oxide semiconductor film which can have a second crystal structure by heat treatment are formed so as to be stacked, and then heat treatment is performed; accordingly, crystal growth occurs with the use of an oxide semiconductor film having the second crystal structure as a seed, so that an oxide semiconductor film having the first crystal structure is formed. An oxide semiconductor film formed in this manner is used for an active layer of the transistor.

Claims

1. A semiconductor device comprising:

a first insulating film;

a second insulating film overlapping with the first insulating film;

a stack of semiconductor films interposed between the first insulating film and the second insulating film, the stack of semiconductor films comprising;

a first oxide semiconductor film; and

a second oxide semiconductor film in contact with the first oxide semiconductor film and interposed between the first oxide semiconductor film and the second insulating film; and

an electrically conducting film overlapping with the stack of semiconductor films with the second insulating film interposed therebetween,

wherein a concentration in nitrogen of the second oxide semiconductor film is higher than a concentration in nitrogen of the first oxide semiconductor film.

5. A semiconductor device according to claim 1, the stack of semiconductor films further comprising a third oxide semiconductor film interposed between the second oxide semiconductor film and the second insulating film,

wherein the concentration in nitrogen of the second oxide semiconductor film is higher than a concentration in nitrogen of the third oxide semiconductor film.

8. A semiconductor device according to claim 1,

wherein the first oxide semiconductor film has a trigonal or hexagonal structure film.

10. A semiconductor device according to claim 1,

wherein the first oxide semiconductor film and the second oxide semiconductor film are non-single-crystals and comprise an amorphous region and a crystal region having c-axis alignment.

12. A semiconductor device according to claim 1,

wherein the first oxide semiconductor film comprises zinc, indium, or gallium.

14. A semiconductor device according to claim 1,

wherein the second oxide semiconductor film is a zinc oxide or an oxynitride semiconductor.

16. An electronic device including the semiconductor device according to claim 1.

2. A semiconductor device comprising:

a first insulating film;

a second insulating film overlapping with the first insulating film;

a stack of semiconductor films interposed between the first insulating film and the second insulating film, the stack of semiconductor films comprising;

a first oxide semiconductor film having a first crystal structure; and

a second oxide semiconductor film having a second crystal structure, in contact with the first oxide semiconductor film and interposed between the first oxide semiconductor film and the second insulating film; and

an electrically conducting film overlapping with the stack of semiconductor films with the second insulating film interposed therebetween,

wherein the first crystal structure is a non-wurtzite structure or a deformed structure of a non-wurtzite structure; and

wherein the second crystal structure is a wurtzite structure.

3. A semiconductor device according to claim 2,

wherein the first crystal structure is one of a YbFe₂O₄ structure, a Yb₂Fe₃O₇ structure, a deformed structure of a YbFe₂O₄ structure, and a deformed structure of a Yb₂Fe₃O₇.

4. A semiconductor device according to claim 2,

wherein a concentration in nitrogen of the second oxide semiconductor film is higher than a concentration in nitrogen of the first oxide semiconductor film.

6. A semiconductor device according to claim 2, the stack of semiconductor films further comprising a third oxide semiconductor film having a third crystal structure interposed between the second oxide semiconductor film and the second insulating film,

wherein the third crystal structure is a non-wurtzite structure or a deformed structure of a non-wurtzite structure.

7. A semiconductor device according to claim 6,

wherein the first crystal structure is one of a YbFe₂O₄ structure, a Yb₂Fe₃O₇ structure, a deformed structure of a YbFe₂O₄ structure, and a deformed structure of a Yb₂Fe₃O₇.

9. A semiconductor device according to claim 2,

wherein the first oxide semiconductor film has a trigonal or hexagonal structure film.

11. A semiconductor device according to claim 2,

wherein the first oxide semiconductor film and the second oxide semiconductor film are non-single-crystals and comprise an amorphous region and a crystal region having c-axis alignment.

13. A semiconductor device according to claim 2,

wherein the first oxide semiconductor film comprises zinc, indium, or gallium.

15. A semiconductor device according to claim 2,

wherein the second oxide semiconductor film is a zinc oxide or an oxynitride semiconductor.

17. An electronic device including the semiconductor device according to claim 2.

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

providing a substrate having an electrically insulating top surface;

forming a first oxide semiconductor film over the substrate in a first atmosphere;

forming a second oxide semiconductor film on and in contact with the first oxide semiconductor film in a second atmosphere having a higher concentration in nitrogen than the first atmosphere;

performing heat treatment to the first oxide semiconductor film and the second oxide semiconductor film so that the first oxide semiconductor film is crystallized in a first crystal structure and the second oxide semiconductor film is crystallized in a second crystal structure different from the first crystal structure,

wherein a concentration in nitrogen of the second oxide semiconductor film is higher than a concentration in nitrogen of the first oxide semiconductor film.

22. A method for manufacturing a semiconductor device according to claim 18, further comprising the steps of:

forming a third oxide semiconductor film on and in contact with the second oxide semiconductor film; and

performing an additional heat treatment on the third oxide semiconductor film so that the third oxide semiconductor film is crystallized in a third crystal structure,

wherein the concentration in nitrogen of the second oxide semiconductor film is higher than a concentration in nitrogen of the third oxide semiconductor film.

25. A method for manufacturing a semiconductor device according to claim 18,

wherein the first oxide semiconductor film has a trigonal or hexagonal structure film.

27. A method for manufacturing a semiconductor device according to claim 18,

wherein the first oxide semiconductor film and the second oxide semiconductor film are non-single-crystals and comprise an amorphous region and a crystal region having c-axis alignment.

29. A method for manufacturing a semiconductor device according to claim 18,

wherein the first oxide semiconductor film comprises zinc, indium, or gallium.

31. A method for manufacturing a semiconductor device according to claim 18,

wherein the second oxide semiconductor film is a zinc oxide or an oxynitride semiconductor.

33. A method for manufacturing a semiconductor device according to claim 18,

wherein the first oxide semiconductor film and the second oxide semiconductor film are formed successively by a sputtering method;

and

wherein nitrogen is introduced in a formation chamber to form the second oxide semiconductor film after that the first oxide semiconductor film has been formed.

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

providing a substrate having an electrically insulating top surface;

forming a first oxide semiconductor film over the substrate in a first atmosphere;

forming a second oxide semiconductor film on and in contact with the first oxide semiconductor film in a second atmosphere having a higher concentration in nitrogen than the first atmosphere;

performing heat treatment to the first oxide semiconductor film and the second oxide semiconductor film so that the first oxide semiconductor film is crystallized in a first crystal structure and the second oxide semiconductor film is crystallized in a second crystal structure,

wherein the first crystal structure is a non-wurtzite structure or a deformed structure of a non-wurtzite structure; and

wherein the second crystal structure is a wurtzite structure.

20. A method for manufacturing a semiconductor device according to claim 19,

wherein the first crystal structure is one of a YbFe₂O₄ structure, a Yb₂Fe₃O₇ structure, a deformed structure of a YbFe₂O₄ structure, and a deformed structure of a Yb₂Fe₃O₇.

21. A method for manufacturing a semiconductor device according to claim 19,

wherein a concentration in nitrogen of the second oxide semiconductor film is higher than a concentration in nitrogen of the first oxide semiconductor film.

23. A method for manufacturing a semiconductor device according to claim 19, further comprising the steps of:

forming a third oxide semiconductor film on and in contact with the second oxide semiconductor film; and

performing an additional heat treatment on the third oxide semiconductor film so that the third oxide semiconductor film is crystallized in a third crystal structure,

wherein the third crystal structure is a non-wurtzite structure or a deformed structure of a non-wurtzite structure.

24. A method for manufacturing a semiconductor device according to claim 23,

wherein the third crystal structure is one of a YbFe₂O₄ structure, a Yb₂Fe₃O₇ structure, a deformed structure of a YbFe₂O₄ structure, and a deformed structure of a Yb₂Fe₃O₇.

26. A method for manufacturing a semiconductor device according to claim 19,

wherein the first oxide semiconductor film has a trigonal or hexagonal structure film.

28. A method for manufacturing a semiconductor device according to claim 19,

wherein the first oxide semiconductor film and the second oxide semiconductor film are non-single-crystals and comprise an amorphous region and a crystal region having c-axis alignment.

30. A method for manufacturing a semiconductor device according to claim 19,

wherein the first oxide semiconductor film comprises zinc, indium, or gallium.

32. A method for manufacturing a semiconductor device according to claim 19,

wherein the second oxide semiconductor film is a zinc oxide or an oxynitride semiconductor.

34. A method for manufacturing a semiconductor device according to claim 19,

wherein the first oxide semiconductor film and the second oxide semiconductor film are formed successively by a sputtering method;

and

wherein nitrogen is introduced in a formation chamber to form the second oxide semiconductor film after that the first oxide semiconductor film has been formed.