Semiconductor device and method for manufacturing semiconductor device

Patent metadata

Field	Value
Publication number	US-9559193-B2
Application number	US-201414576400-A
Country	US
Kind code	B2
Filing date	Dec 19, 2014
Priority date	Apr 22, 2011
Publication date	Jan 31, 2017
Grant date	Jan 31, 2017

Abstract

A semiconductor device having a transistor including an oxide semiconductor film is disclosed. In the semiconductor device, the oxide semiconductor film is provided along a trench formed in an insulating layer. The trench includes a lower end corner portion and an upper end corner portion having a curved shape with a curvature radius of longer than or equal to 20 nm and shorter than or equal to 60 nm, and the oxide semiconductor film is provided in contact with a bottom surface, the lower end corner portion, the upper end corner portion, and an inner wall surface of the trench. The oxide semiconductor film includes a crystal having a c-axis substantially perpendicular to a surface at least over the upper end corner portion.

First claim

What is claimed is:

1. A method for manufacturing a semiconductor device comprising steps of:
forming an insulating layer comprising a curved surface;
performing a plasma treatment using a rare gas element on the curved surface;
forming an oxide semiconductor film over and in contact with the curved surface after the plasma treatment,
wherein the curved surface has a curvature radius of longer than or equal to 20 nm and shorter than or equal to 60 nm,
wherein the oxide semiconductor film comprises a crystalline region,
wherein the crystalline region comprises a plurality of layers of metal atoms, and
wherein each of the plurality of layers is formed along the curved surface.

2. The method for manufacturing a semiconductor device according to claim 1 , further comprising steps of:
removing hydrogen in the oxide semiconductor film by a heat treatment in a nitrogen atmosphere or a rare gas atmosphere, and
supplying oxygen to the oxide semiconductor film after the heat treatment.

3. The method for manufacturing a semiconductor device according to claim 1 ,
wherein c-axes of crystals in the crystalline region are aligned substantially perpendicular to the curved surface.

4. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the curved surface is curved upward.

5. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the curved surface is curved downward.

6. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the oxide semiconductor film is formed by an atomic layer deposition method.

7. The method for manufacturing a semiconductor device according to claim 1 ,
wherein the oxide semiconductor film contains indium.

8. A method for manufacturing a semiconductor device comprising steps of:
forming an insulating layer comprising a curved surface;
performing a plasma treatment using a rare gas element on the curved surface;
forming an oxide semiconductor film over and in contact with the curved surface after the plasma treatment,
wherein the curved surface has a curvature radius of longer than or equal to 20 nm and shorter than or equal to 60 nm,
wherein the oxide semiconductor film comprises a crystalline region including crystals whose c-axes are substantially parallel to a normal vector of the curved surface, and
wherein a growth surface of the crystals is along the curved surface.

9. The method for manufacturing a semiconductor device according to claim 8 , further comprising steps of:
removing hydrogen in the oxide semiconductor film by a heat treatment in a nitrogen atmosphere or a rare gas atmosphere, and
supplying oxygen to the oxide semiconductor film after the heat treatment.

10. The method for manufacturing a semiconductor device according to claim 8 ,
wherein the curved surface is curved upward.

11. The method for manufacturing a semiconductor device according to claim 8 ,
wherein the curved surface is curved downward.

12. The method for manufacturing a semiconductor device according to claim 8 ,
wherein the oxide semiconductor film is formed by an atomic layer deposition method.

13. The method for manufacturing a semiconductor device according to claim 8 ,
wherein the oxide semiconductor film contains indium.

14. A method for manufacturing a semiconductor device comprising steps of:
forming an insulating layer comprising a curved surface;
performing a plasma treatment using a rare gas element on the curved surface;
forming an oxide semiconductor film over and in contact with the curved surface after the plasma treatment;
forming a gate insulating film; and
forming a gate electrode facing the oxide semiconductor film with the gate insulating film interposed therebetween,
wherein the curved surface has a curvature radius of longer than or equal to 20 nm and shorter than or equal to 60 nm,
wherein the oxide semiconductor film comprises a crystalline region,
wherein the crystalline region comprises a plurality of layers of metal atoms, and
wherein each of the plurality of layers is formed along the curved surface.

15. The method for manufacturing a semiconductor device according to claim 14 , further comprising steps of:
removing hydrogen in the oxide semiconductor film by a heat treatment in a nitrogen atmosphere or a rare gas atmosphere, and
supplying oxygen to the oxide semiconductor film after the heat treatment.

16. The method for manufacturing a semiconductor device according to claim 14 ,
wherein c-axes of crystals in the crystalline region are aligned substantially perpendicular to the curved surface.

17. The method for manufacturing a semiconductor device according to claim 14 ,
wherein the curved surface is curved upward.

18. The method for manufacturing a semiconductor device according to claim 14 ,
wherein the curved surface is curved downward.

19. The method for manufacturing a semiconductor device according to claim 14 ,
wherein at least one of the oxide semiconductor film and the gate insulating film is formed by an atomic layer deposition method.

20. The method for manufacturing a semiconductor device according to claim 1 , wherein the curved surface has an average surface roughness of more than or equal to 0.1 nm and less than 0.5 nm.

21. The method for manufacturing a semiconductor device according to claim 8 , wherein the curved surface has an average surface roughness of more than or equal to 0.1 nm and less than 0.5 nm.

22. The method for manufacturing a semiconductor device according to claim 14 , wherein the curved surface has an average surface roughness of more than or equal to 0.1 nm and less than 0.5 nm.

Assignees

• Semiconductor Energy Lab

Inventors

• Isobe Atsuo
• Sasaki Toshinari
• Sasagawa Shinya
• Ishizuka Akihiro

Classifications

• H10P95/90

  Thermal treatments, e.g. annealing or sintering · CPC title

• H10P14/3434

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

• H10P14/24

  using chemical vapour deposition [CVD] · CPC title

• H10D62/875

  being semiconductor metal oxide, e.g. InGaZnO (Group II-VI materials H10D62/86; Group I-VI materials H10D62/871; Pb compounds or alloys H10D62/874) · CPC title

• H10D30/6755

  Oxide semiconductors, e.g. zinc oxide, copper aluminium oxide or cadmium stannate · CPC title