Electronic device, manufacturing method of electronic device, and sputtering target

• US 8,883,555 B2
• Filed: 08/17/2011
• Issued: 11/11/2014
• Est. Priority Date: 08/25/2010
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): KUO, WENSING W
• Application Number:
  US13/211,542
• Publication Number:
  US 20120049183A1
• Time in Patent Office: 1,182 Days
• Field of Search: None
• US Class Current: 438/104
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• 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 29/247 Amorphous materials
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/66742 Thin film unipolar transistors
• 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 29/78693 the semiconducting oxide being amorphous

Abstract

A film formation is performed using a target in which a material which is volatilized more easily than gallium when heated at 400° C. to 700° C., such as zinc, is added to gallium oxide by a sputtering method with high mass-productivity which can be applied to a large-area substrate, such as a DC sputtering method or a pulsed DC sputtering method. This film is heated at 400° C. to 700° C., whereby the added material is segregated in the vicinity of a surface of the film. Another portion of the film has a decreased concentration of the added material and a sufficiently high insulating property; therefore, it can be used for a gate insulator of a semiconductor device, or the like.

Claims

1. A manufacturing method of an electronic device comprising the steps of:

forming an oxide film by an AC sputtering method or a DC sputtering method using an oxide target comprising at least a first metal element and a second metal element;

performing heat treatment on the oxide film; and

etching a surface of the oxide film to form an insulating oxide film,

wherein the concentration of the first metal element in the insulating oxide film is lower than or equal to 50% of the concentration of the first metal element in the oxide target.

2. The manufacturing method of an electronic device according to claim 1, further comprising a step of forming a semi-conductive oxide film in contact with the insulating oxide film.

3. The manufacturing method of an electronic device according to claim 2,

wherein the semi-conductive oxide film comprises indium and zinc.

4. The manufacturing method of an electronic device according to claim 1,

wherein the first metal element is zinc.

5. The manufacturing method of an electronic device according to claim 1,

wherein the second metal element is gallium.

6. The manufacturing method of an electronic device according to claim 1,

wherein the heat treatment is performed at higher than or equal to 200°

C.

7. A manufacturing method of an electronic device comprising the steps of:

forming an oxide film by an AC sputtering method or a DC sputtering method using an oxide target comprising at least a first metal element and a second metal element;

performing heat treatment on the oxide film; and

etching a surface of the oxide film to form an insulating oxide film,

wherein the conductivity of the oxide target is higher than the conductivity of the insulating oxide film.

8. The manufacturing method of an electronic device according to claim 7, further comprising a step of forming a semi-conductive oxide film in contact with the insulating oxide film.

9. The manufacturing method of an electronic device according to claim 8,

wherein the semi-conductive oxide film comprises indium and zinc.

10. The manufacturing method of an electronic device according to claim 7,

wherein the first metal element is zinc.

11. The manufacturing method of an electronic device according to claim 7,

wherein the second metal element is gallium.

12. The manufacturing method of an electronic device according to claim 7,

wherein the heat treatment is performed at higher than or equal to 200°

C.

13. The manufacturing method of an electronic device according to claim 7, wherein a concentration of the first metal element in the insulating oxide film is lower than a concentration of the first metal element in the oxide target.

14. A manufacturing method of an electronic device comprising the steps of:

forming an oxide film by an AC sputtering method or a DC sputtering method using an oxide target comprising at least a first metal element and a second metal element; and

reducing the concentration of the first metal element of the oxide film by performing heat treatment on the oxide film to form an insulating oxide film.

15. The manufacturing method of an electronic device according to claim 14, further comprising a step of forming a semi-conductive oxide film in contact with the insulating oxide film.

16. The manufacturing method of an electronic device according to claim 15,

wherein the semi-conductive oxide film comprises indium and zinc.

17. The manufacturing method of an electronic device according to claim 14,

wherein the first metal element is zinc.

18. The manufacturing method of an electronic device according to claim 14,

wherein the second metal element is gallium.

19. The manufacturing method of an electronic device according to claim 14,

wherein the heat treatment is performed at higher than or equal to 200°

C.

20. A manufacturing method of an electronic device comprising the steps of:

forming an oxide film by an AC sputtering method or a DC sputtering method using an oxide target comprising at least a first metal element and a second metal element;

performing heat treatment on the oxide film to form a region in which the concentration of the first metal element is high; and

forming a semi-conductive oxide film in contact with the oxide film,

wherein the molar ratio of the second metal element in the semi-conductive oxide film is greater than or equal to 0.2.

21. The manufacturing method of an electronic device according to claim 20,

wherein the semi-conductive oxide film comprises indium and zinc.

22. The manufacturing method of an electronic device according to claim 20,

wherein the first metal element is zinc.

23. The manufacturing method of an electronic device according to claim 20,

wherein the second metal element is gallium.

24. The manufacturing method of an electronic device according to claim 20,

wherein the heat treatment is performed at higher than or equal to 200°

C.

25. A manufacturing method of an electronic device comprising the steps of:

forming an oxide film by sputtering method using an oxide target comprising at least zinc and gallium;

performing heat treatment on the oxide film;

etching a surface of the oxide film to form an insulating oxide film,

wherein the concentration of zinc in the insulating oxide film is lower than or equal to 50% of the concentration of zinc in the oxide target.