Oxide semiconductor film and semiconductor device

• US 8,680,522 B2
• Filed: 03/15/2013
• Issued: 03/25/2014
• Est. Priority Date: 12/03/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Tsubuku, Masashi, Akimoto, Kengo, Ohara, Hiroki, Honda, Tatsuya, Omata, Takatsugu, Nonaka, Yusuke, Takahashi, Masahiro, Miyanaga, Akiharu
• Primary Examiner(s): LE, DUNG ANH
• Application Number:
  US13/832,479
• Publication Number:
  US 20130214273A1
• Time in Patent Office: 375 Days
• Field of Search: 257/43, 257/57, 257/59, 257/72, 257/77, 257/347, 438/151, 438/458, 438/585, 438/770, 438/787, 438/795
• US Class Current: 257/43
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/1033 with insulated gate, e.g. characterised by the length, the width, the geometric contour or the doping structure with channel and gate aligned in the lengthwise direction H01L29/42376; with buried channel H01L29/7838
• CPC Class Codes: H01L 29/247 Amorphous materials
• 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
• CPC Class Codes: H01L 29/78696 characterised by the structure of the channel, e.g. multichannel, transverse or longitudinal shape, length or width, doping structure, or the overlap or alignment between the channel and the gate, the source or the drain, or the contacting structure of the channel H01L29/78612 takes precedence; transistors having a drain offset region or a lightly doped drain [LDD] H01L29/78621

Abstract

An oxide semiconductor film which has more stable electric conductivity is provided. Further, a semiconductor device which has stable electric characteristics and high reliability is provided by using the oxide semiconductor film. An oxide semiconductor film includes a crystalline region, and the crystalline region includes a crystal in which an a-b plane is substantially parallel with a surface of the film and a c-axis is substantially perpendicular to the surface of the film; the oxide semiconductor film has stable electric conductivity and is more electrically stable with respect to irradiation with visible light, ultraviolet light, and the like. By using such an oxide semiconductor film for a transistor, a highly reliable semiconductor device having stable electric characteristics can be provided.

Claims

1. A semiconductor device comprising:

a gate electrode;

an oxide semiconductor film comprising a first crystalline region and a second crystalline region; and

a gate insulating film between the gate electrode and the oxide semiconductor film,

wherein each of the first crystalline region and the second crystalline region includes a crystal structure in which a c-axis is substantially perpendicular to a surface of the oxide semiconductor film,

wherein the oxide semiconductor film is in a non-single-crystal state,

wherein an a-axis direction of the first crystalline region is different from an a-axis direction of the second crystalline region, and

wherein a b-axis direction of the first crystalline region is different from a b-axis direction of the second crystalline region.

2. The semiconductor device according to claim 1, wherein a concentration of lithium in the oxide semiconductor film is 5×

10¹⁵ atoms/cm³ or lower.

3. The semiconductor device according to claim 1, wherein a concentration of sodium in the oxide semiconductor film is 5×

10¹⁶ atoms/cm³ or lower.

4. The semiconductor device according to claim 1, wherein a concentration of potassium in the oxide semiconductor film is 5×

10¹⁵ atoms/cm³ or lower.

5. The semiconductor device according to claim 1, further comprising a metal oxide film in contact with the oxide semiconductor film,

wherein an energy gap of the metal oxide film is larger than an energy gap of the oxide semiconductor film.

6. The semiconductor device according to claim 1, wherein a size of the first crystalline region is greater than or equal to 1 nm and less than or equal to 1000 nm.

7. The semiconductor device according to claim 1, wherein an angle between the c-axis and a normal of the surface of the oxide semiconductor film is greater than or equal to 0°

and less than or equal to 20°

.

8. The semiconductor device according to claim 1, wherein the oxide semiconductor film is substantially intrinsic.

9. The semiconductor device according to claim 1,

wherein alignment along an a-b plane of the crystal structure is not indicated by a X-ray diffraction spectrum of the oxide semiconductor film, and

wherein the X-ray diffraction spectrum is measured by an in-plane method while rotating the oxide semiconductor film using the c-axis as a rotation axis.

10. A semiconductor device comprising:

a gate electrode;

an oxide semiconductor film comprising a first crystalline region and a second crystalline region; and

a gate insulating film between the gate electrode and the oxide semiconductor film,

wherein each of the first crystalline region and the second crystalline region includes a crystal structure in which a c-axis is substantially perpendicular to a surface of the oxide semiconductor film,

wherein the oxide semiconductor film is in a non-single-crystal state,

wherein an a-axis direction of the first crystalline region is different from an a-axis direction of the second crystalline region,

wherein a b-axis direction of the first crystalline region is different from a b-axis direction of the second crystalline region, and

wherein a concentration of hydrogen in the oxide semiconductor film is 5×

10¹⁹ atoms/cm³ or lower.

11. The semiconductor device according to claim 10, wherein a concentration of lithium in the oxide semiconductor film is 5×

10¹⁵ atoms/cm³ or lower.

12. The semiconductor device according to claim 10, wherein a concentration of sodium in the oxide semiconductor film is 5×

10¹⁶ atoms/cm³ or lower.

13. The semiconductor device according to claim 10, wherein a concentration of potassium in the oxide semiconductor film is 5×

10¹⁵ atoms/cm³ or lower.

14. The semiconductor device according to claim 10, further comprising a metal oxide film in contact with the oxide semiconductor film,

wherein an energy gap of the metal oxide film is larger than an energy gap of the oxide semiconductor film.

15. The semiconductor device according to claim 10, wherein a size of the first crystalline region is greater than or equal to 1 nm and less than or equal to 1000 nm.

16. The semiconductor device according to claim 10, wherein an angle between the c-axis and a normal of the surface of the oxide semiconductor film is greater than or equal to 0°

and less than or equal to 20°

.

17. The semiconductor device according to claim 10, wherein the oxide semiconductor film is substantially intrinsic.

18. The semiconductor device according to claim 10,

wherein alignment along an a-b plane of the crystal structure is not indicated by a X-ray diffraction spectrum of the oxide semiconductor film, and

wherein the X-ray diffraction spectrum is measured by an in-plane method while rotating the oxide semiconductor film using the c-axis as a rotation axis.

19. A semiconductor device comprising:

a gate electrode;

an oxide semiconductor film comprising a first crystalline region and a second crystalline region; and

a gate insulating film between the gate electrode and the oxide semiconductor film,

wherein each of the first crystalline region and the second crystalline region includes a crystal structure in which a c-axis is substantially perpendicular to a surface of the oxide semiconductor film,

wherein the oxide semiconductor film is in a non-single-crystal state,

wherein an a-axis direction of the first crystalline region is different from an a-axis direction of the second crystalline region,

wherein a b-axis direction of the first crystalline region is different from a b-axis direction of the second crystalline region, and

wherein a spin density of a signal in a region where a g value is in the vicinity of 1.93 in ESR measurement of the oxide semiconductor film is lower than 1.3×

10¹⁸ spins/cm³.

20. The semiconductor device according to claim 19, wherein a concentration of lithium in the oxide semiconductor film is 5×

10¹⁵ atoms/cm³ or lower.

21. The semiconductor device according to claim 19, wherein a concentration of sodium in the oxide semiconductor film is 5×

10¹⁶ atoms/cm³ or lower.

22. The semiconductor device according to claim 19, wherein a concentration of potassium in the oxide semiconductor film is 5×

10¹⁵ atoms/cm³ or lower.

23. The semiconductor device according to claim 19, further comprising a metal oxide film in contact with the oxide semiconductor film,

wherein an energy gap of the metal oxide film is larger than an energy gap of the oxide semiconductor film.

24. The semiconductor device according to claim 19, wherein a size of the first crystalline region is greater than or equal to 1 nm and less than or equal to 1000 nm.

25. The semiconductor device according to claim 19, wherein an angle between the c-axis and a normal of the surface of the oxide semiconductor film is greater than or equal to 0°

and less than or equal to 20°

.

26. The semiconductor device according to claim 19, wherein the oxide semiconductor film is substantially intrinsic.

27. The semiconductor device according to claim 19,

wherein alignment along an a-b plane of the crystal structure is not indicated by a X-ray diffraction spectrum of the oxide semiconductor film, and

wherein the X-ray diffraction spectrum is measured by an in-plane method while rotating the oxide semiconductor film using the c-axis as a rotation axis.

28. A semiconductor device comprising:

a gate electrode;

an oxide semiconductor film comprising a first crystalline region and a second crystalline region; and

a gate insulating film between the gate electrode and the oxide semiconductor film,

wherein each of the first crystalline region and the second crystalline region includes a crystal structure in which a c-axis is substantially perpendicular to a surface of the oxide semiconductor film,

wherein the oxide semiconductor film is in a non-single-crystal state,

wherein an a-axis direction of the first crystalline region is different from an a-axis direction of the second crystalline region,

wherein a b-axis direction of the first crystalline region is different from a b-axis direction of the second crystalline region, and

wherein a concentration of an alkali metal in the oxide semiconductor film is 5×

10¹⁶ atoms/cm³ or lower.

29. The semiconductor device according to claim 28, wherein a concentration of lithium in the oxide semiconductor film is 5×

10¹⁵ atoms/cm³ or lower.

30. The semiconductor device according to claim 28, wherein a concentration of sodium in the oxide semiconductor film is 5×

10¹⁶ atoms/cm³ or lower.

31. The semiconductor device according to claim 28, wherein a concentration of potassium in the oxide semiconductor film is 5×

10¹⁵ atoms/cm³ or lower.

32. The semiconductor device according to claim 28, further comprising a metal oxide film in contact with the oxide semiconductor film,

wherein an energy gap of the metal oxide film is larger than an energy gap of the oxide semiconductor film.

33. The semiconductor device according to claim 28, wherein a size of the first crystalline region is greater than or equal to 1 nm and less than or equal to 1000 nm.

34. The semiconductor device according to claim 28, wherein an angle between the c-axis and a normal of the surface of the oxide semiconductor film is greater than or equal to 0°

and less than or equal to 20°

.

35. The semiconductor device according to claim 28, wherein the oxide semiconductor film is substantially intrinsic.

36. The semiconductor device according to claim 28,

wherein alignment along an a-b plane of the crystal structure is not indicated by a X-ray diffraction spectrum of the oxide semiconductor film, and

wherein the X-ray diffraction spectrum is measured by an in-plane method while rotating the oxide semiconductor film using the c-axis as a rotation axis.