Semiconductor device and method for manufacturing semiconductor device

Patent metadata

Field	Value
Publication number	US-9281358-B2
Application number	US-201414270697-A
Country	US
Kind code	B2
Filing date	May 6, 2014
Priority date	Nov 30, 2010
Publication date	Mar 8, 2016
Grant date	Mar 8, 2016

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.

First claim

The invention claimed is:

1. 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.

2. A method for manufacturing a semiconductor device according to claim 1 ,
wherein the first crystal structure is one of a YbFe 2 O 4 structure, a Yb 2 Fe 3 O 7 structure, a deformed structure of a YbFe 2 O 4 structure, and a deformed structure of a Yb 2 Fe 3 O 7 .

3. A method for manufacturing a semiconductor device according to claim 1 ,
wherein a concentration in nitrogen of the second oxide semiconductor film is higher than a concentration in nitrogen of the first oxide semiconductor film.

4. A method for manufacturing a semiconductor device according to claim 1 ,
wherein the first oxide semiconductor film has a trigonal or hexagonal structure film.

5. A method for manufacturing 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.

6. A method for manufacturing a semiconductor device according to claim 1 ,
wherein the first oxide semiconductor film comprises zinc, indium, or gallium.

7. A method for manufacturing a semiconductor device according to claim 1 ,
wherein the second oxide semiconductor film is a zinc oxide or an oxynitride semiconductor.

8. A method for manufacturing a semiconductor device according to claim 1 ,
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.

9. A method for manufacturing a semiconductor device according to claim 1 , 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.

10. A method for manufacturing a semiconductor device according to claim 9 ,
wherein the third crystal structure is one of a YbFe 2 O 4 structure, a Yb 2 Fe 3 O 7 structure, a deformed structure of a YbFe 2 O 4 structure, and a deformed structure of a Yb 2 Fe 3 O 7 .

11. A semiconductor device comprising:
a first oxide semiconductor film having a first crystal structure;
a second oxide semiconductor film on and in contact with the first oxide semiconductor film, the second oxide semiconductor film having a second crystal structure; and
a gate electrode overlapping with the first oxide semiconductor film and the second oxide semiconductor film,
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.

12. A semiconductor device according to claim 11 ,
wherein the first crystal structure is one of a YbFe 2 O 4 structure, a Yb 2 Fe 3 O 7 structure, a deformed structure of a YbFe 2 O 4 structure, and a deformed structure of a Yb 2 Fe 3 O 7 .

13. A semiconductor device according to claim 11 ,
wherein a concentration in nitrogen of the second oxide semiconductor film is higher than a concentration in nitrogen of the first oxide semiconductor film.

14. A semiconductor device according to claim 11 ,
wherein the first oxide semiconductor film has a trigonal or hexagonal structure film.

15. A semiconductor device according to claim 11 ,
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.

16. A semiconductor device according to claim 11 ,
wherein the first oxide semiconductor film comprises zinc, indium, or gallium.

17. A semiconductor device according to claim 11 ,
wherein the second oxide semiconductor film is a zinc oxide or an oxynitride semiconductor.

18. A semiconductor device according to claim 11 , further comprising a third oxide semiconductor film on the second oxide semiconductor film, the third oxide semiconductor film having a third crystal structure,
wherein the third crystal structure is a non-wurtzite structure or a deformed structure of a non-wurtzite structure.

19. A semiconductor device according to claim 18 ,
wherein the first crystal structure is one of a YbFe 2 O 4 structure, a Yb 2 Fe 3 O 7 structure, a deformed structure of a YbFe 2 O 4 structure, and a deformed structure of a Yb 2 Fe 3 O 7 .

20. 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.

21. A semiconductor device according to claim 20 ,
wherein the first crystal structure is one of a YbFe 2 O 4 structure, a Yb 2 Fe 3 O 7 structure, a deformed structure of a YbFe 2 O 4 structure, and a deformed structure of a Yb 2 Fe 3 O 7 .

22. A semiconductor device according to claim 20 ,
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 semiconductor device according to claim 20 ,
wherein the first oxide semiconductor film has a trigonal or hexagonal structure film.

24. A semiconductor device according to claim 20 ,
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.

25. A semiconductor device according to claim 20 ,
wherein the first oxide semiconductor film c

Assignees

• Semiconductor Energy Lab

Inventors

• Yamazaki Shunpei
• Takahashi Masahiro
• Maruyama Tetsunori

Classifications

• H10P14/3452

  Microstructure · CPC title

• H10P14/3434

  being oxide semiconductor materials (Group IIB-VIA semiconductor materials H10P14/3424) · CPC title

• H10P14/3426

  Oxides · CPC title

• H10P14/3256

  Microstructure · CPC title

• H10P14/3248

  consisting of two layers · CPC title