Semiconductor device and method for manufacturing semiconductor device

• US 9,559,193 B2
• Filed: 12/19/2014
• Issued: 01/31/2017
• Est. Priority Date: 04/22/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Isobe, Atsuo, Sasaki, Toshinari, Sasagawa, Shinya, Ishizuka, Akihiro
• Primary Examiner(s): Slutsker, Julia
• Application Number:
  US14/576,400
• Publication Number:
  US 20150171195A1
• Time in Patent Office: 774 Days
• Field of Search: 438/270, 438/104, 438/149
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/477 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/38 - H01L21/449 and H01L21/461 - H01L21/475 take precedence
• 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 29/045 by their particular orientation of crystalline planes
• 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 29/66969 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: H10B 41/70 the floating gate being an electrode shared by two or more components

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.

Claims

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.

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.

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.

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.

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.

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.