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

• US 9,640,668 B2
• Filed: 10/27/2014
• Issued: 05/02/2017
• Est. Priority Date: 08/25/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): PERT, EVAN T
• Application Number:
  US14/524,224
• Publication Number:
  US 20150041808A1
• Time in Patent Office: 918 Days
• 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. An electronic device comprising:

a substrate;

an oxide film over the substrate; and

a semi-conductive oxide film over and in contact with the oxide film,

wherein the oxide film comprises at least a first metal element and a second metal element,

wherein a portion in contact with the semi-conductive oxide film has higher concentration of the first metal element in the oxide film than a portion facing the substrate, and

wherein the portion in contact with the semi-conductive oxide film has lower concentration of the second metal element in the oxide film than the portion facing the substrate.

2. The electronic device according to claim 1, wherein the semi-conductive oxide film has an amorphous state.

3. The electronic device according to claim 1, wherein the semi-conductive oxide film is in a single-crystal state.

4. The electronic device according to claim 1, wherein the semi-conductive oxide film has a crystal.

5. The electronic device according to claim 1, wherein the semi-conductive oxide film has a crystal which is c-axis-aligned.

6. The electronic device according to claim 1, wherein the oxide film has a concentration gradient of the first metal element.

7. The electronic device according to claim 1, wherein the first metal element is zinc and the second metal element is gallium.

8. An electronic device comprising:

a substrate;

a gate electrode over the substrate;

a gate insulator over the gate electrode;

an oxide film over the gate insulator; and

a semi-conductive oxide film over and in contact with the oxide film,

wherein the oxide film comprises at least a first metal element and a second metal element,

wherein a portion in contact with the semi-conductive oxide film has higher concentration of the first metal element in the oxide film than a portion facing the substrate, and

wherein the portion in contact with the semi-conductive oxide film has lower concentration of the second metal element in the oxide film than the portion facing the substrate.

9. The electronic device according to claim 8, wherein the semi-conductive oxide film has an amorphous state.

10. The electronic device according to claim 8, wherein the semi-conductive oxide film is in a single-crystal state.

11. The electronic device according to claim 8, wherein the semi-conductive oxide film has a crystal.

12. The electronic device according to claim 8, wherein the semi-conductive oxide film has a crystal which is c-axis-aligned.

13. The electronic device according to claim 8, wherein the oxide film has a concentration gradient of the first metal element.

14. The electronic device according to claim 8, wherein the first metal element is zinc and the second metal element is gallium.

15. An electronic device comprising:

a substrate;

a gate electrode over the substrate;

a gate insulator over the gate electrode;

an oxide film over the gate insulator;

a semi-conductive oxide film over and in contact with the oxide film;

n-type semi-conductive oxide films over and in contact with the semi-conductive oxide film,

wherein the oxide film comprises at least a first metal element and a second metal element,

wherein a portion in contact with the semi-conductive oxide film has higher concentration of the first metal element in the oxide film than a portion facing the substrate, and

wherein the portion in contact with the semi-conductive oxide film has lower concentration of the second metal element in the oxide film than the portion facing the substrate.

16. The electronic device according to claim 15, wherein the semi-conductive oxide film has an amorphous state.

17. The electronic device according to claim 15, wherein the semi-conductive oxide film is in a single-crystal state.

18. The electronic device according to claim 15, wherein the semi-conductive oxide film has a crystal.

19. The electronic device according to claim 15, wherein the semi-conductive oxide film has a crystal which is c-axis-aligned.

20. The electronic device according to claim 15, wherein the oxide film has a concentration gradient of the first metal element.

21. The electronic device according to claim 15, wherein the first metal element is zinc and the second metal element is gallium.