Oxide semiconductor film and semiconductor device

• US 9,478,668 B2
• Filed: 04/03/2012
• Issued: 10/25/2016
• Est. Priority Date: 04/13/2011
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Takahashi, Masahiro, Akimoto, Kengo, Yamazaki, Shunpei
• Primary Examiner(s): Sandvik, Benjamin
• Assistant Examiner(s): ASSOUMAN, HERVE-LOUIS Y
• Application Number:
  US13/438,206
• Publication Number:
  US 20120261657A1
• Time in Patent Office: 1,666 Days
• Field of Search: 257/43, 257/E29.105, 257/204, 257/64, 257/192, 257/59, 438/104, 438/197, 438/604
• US Class Current: 1/1
• CPC Class Codes: C01G 15/006 Compounds containing, besides gallium, indium, or thallium, two or more other elements, with the exception of oxygen or hydrogen
• CPC Class Codes: C01P 2006/40 Electric properties
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G02F 2201/123 pixel
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02609 Crystal orientation
• 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 27/1285 using control of the annealing or irradiation parameters, e.g. using different scanning direction or intensity for different transistors
• 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: 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
• CPC Class Codes: H10K 59/1213 the pixel elements being TFTs

Abstract

To provide an oxide semiconductor film having stable electric conductivity and a highly reliable semiconductor device having stable electric characteristics by using the oxide semiconductor film. The oxide semiconductor film contains indium (In), gallium (Ga), and zinc (Zn) and includes a c-axis-aligned crystalline region aligned in the direction parallel to a normal vector of a surface where the oxide semiconductor film is formed. Further, the composition of the c-axis-aligned crystalline region is represented by In_1+δGa_1-δO₃(ZnO)_m (0<δ<1 and m=1 to 3 are satisfied), and the composition of the entire oxide semiconductor film including the c-axis-aligned crystalline region is represented by In_xGa_yO₃(ZnO)_m (0<x<2, 0<y<2, and m=1 to 3 are satisfied).

Claims

1. An oxide semiconductor film comprising a crystalline region,

wherein the crystalline region comprises a crystal,

wherein a c-axis of the crystal is oriented substantially in a direction parallel to a normal vector of a surface where the oxide semiconductor film is formed,

wherein a composition of the crystalline region is represented by In_1+δ

Ga_1-δ

O₃(ZnO)_m (0<

δ

<

1 and m=1 to 3 are satisfied),

wherein a composition of the oxide semiconductor film is represented by In_xGa_yO₃(ZnO)_m (0<

x<

2, 0<

y<

2, and m=1 to 3 are satisfied), and

wherein the composition of the crystalline region is different from the composition of the entire oxide semiconductor film.

2. The oxide semiconductor film according to claim 1, wherein a total concentration of phosphorus, boron, and nitrogen contained in the oxide semiconductor film is lower than or equal to 5×

10¹⁹ atoms/cm³.

3. The oxide semiconductor film according to claim 1, wherein a total concentration of phosphorus, boron, and nitrogen contained in the oxide semiconductor film is lower than or equal to 5×

10¹⁸ atoms/cm³.

4. The oxide semiconductor film according to claim 1, wherein a concentration of any one of phosphorus, boron, and nitrogen contained in the oxide semiconductor film is lower than or equal to 1×

10¹⁹ atoms/cm³.

5. The oxide semiconductor film according to claim 1, wherein concentrations of lithium and potassium contained in the oxide semiconductor film are lower than or equal to 5×

10¹⁵ atoms/cm³.

6. The oxide semiconductor film according to claim 1, wherein a concentration of sodium contained in the oxide semiconductor film is lower than or equal to 5×

10¹⁶ atoms/cm³.

7. A semiconductor device comprising:

a gate electrode;

an oxide semiconductor film;

a first insulating film between the gate electrode and the oxide semiconductor film; and

a second insulating film over the oxide semiconductor film,

wherein the oxide semiconductor film comprises a crystalline region,

wherein the crystalline region comprises a crystal,

wherein a c-axis of the crystal is oriented substantially in a direction parallel to a normal vector of a surface of the first insulating film,

wherein a composition of the crystalline region is represented by In_1+δ

Ga_1-δ

O₃(ZnO)_m (0<

δ

<

1 and m=1 to 3 are satisfied),

wherein a composition of the oxide semiconductor film is represented by In_xGa_yO₃(ZnO)_m (0<

x<

2, 0<

y<

2, and m=1 to 3 are satisfied), and

wherein the composition of the crystalline region is different from the composition of the entire oxide semiconductor film.

8. The semiconductor device according to claim 7, wherein a total concentration of boron, phosphorus, and nitrogen contained in the oxide semiconductor film is lower than or equal to 5×

10¹⁹ atoms/cm³.

9. The semiconductor device according to claim 7, wherein a total concentration of boron, phosphorus, and nitrogen contained in the oxide semiconductor film is lower than or equal to 5×

10¹⁸ atoms/cm³.

10. The semiconductor device according to claim 7, wherein a concentration of any one of boron, phosphorus, and nitrogen contained in the oxide semiconductor film is lower than or equal to 1×

10¹⁹ atoms/cm³.

11. The semiconductor device according to claim 7, wherein concentrations of lithium and potassium contained in the oxide semiconductor film are lower than or equal to 5×

10¹⁵ atoms/cm³.

12. The semiconductor device according to claim 7, wherein a concentration of sodium contained in the oxide semiconductor film is lower than or equal to 5×

10¹⁶ atoms/cm³.

13. A semiconductor device comprising:

a first insulating film;

an oxide semiconductor film over the first insulating film;

a second insulating film over the oxide semiconductor film; and

a gate electrode over the second insulating film,

wherein the oxide semiconductor film comprises a crystalline region,

wherein the crystalline region comprises a crystal,

wherein a c-axis of the crystal is oriented substantially in a direction parallel to a normal vector of a surface of the first insulating film,

wherein a composition of the crystalline region is represented by In_1+δ

Ga_1-δ

O₃(ZnO)_m (0<

δ

<

1 and m=1 to 3 are satisfied),

wherein a composition of the oxide semiconductor film is represented by In_xGa_yO₃(ZnO)_m (0<

x<

2, 0<

y<

2, and m=1 to 3 are satisfied), and

wherein the composition of the crystalline region is different from the composition of the entire oxide semiconductor film.

14. The semiconductor device according to claim 13, wherein a total concentration of boron, phosphorus, and nitrogen contained in the oxide semiconductor film is lower than or equal to 5×

10¹⁹ atoms/cm³.

15. The semiconductor device according to claim 13, wherein a total concentration of boron, phosphorus, and nitrogen contained in the oxide semiconductor film is lower than or equal to 5×

10¹⁸ atoms/cm³.

16. The semiconductor device according to claim 13, wherein a concentration of any one of boron, phosphorus, and nitrogen contained in the oxide semiconductor film is lower than or equal to 1×

10¹⁹ atoms/cm³.

17. The semiconductor device according to claim 13, wherein concentrations of lithium and potassium contained in the oxide semiconductor film are lower than or equal to 5×

10¹⁵ atoms/cm³.

18. The semiconductor device according to claim 13, wherein a concentration of sodium contained in the oxide semiconductor film is lower than or equal to 5×

10¹⁶ atoms/cm³.

19. The semiconductor device according to claim 13, wherein the first insulating film comprises a surface whose average surface roughness is less than 0.5 nm.