METHOD FOR MANUFACTURING SEMICONDUCTOR DEVICE

• US 20110212570A1
• Filed: 02/17/2011
• Published: 09/01/2011
• Est. Priority Date: 02/26/2010
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: YAMAZAKI, Shunpei, OHARA, Hiroki
• Granted Patent: US 8,518,755 B2
• Time in Patent Office: Days
• US Class Current: 438/104
• CPC Class Codes: H01L 21/02521 Materials
• 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 29/66742 Thin film unipolar transistors
• CPC Class Codes: H01L 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

It is an object to provide a highly reliable semiconductor device, a semiconductor device with low power consumption, a semiconductor device with high productivity, and a method for manufacturing such a semiconductor device. Impurities left remaining in an oxide semiconductor layer are removed without generating oxygen deficiency, and the oxide semiconductor layer is purified to have an extremely high purity. Specifically, after oxygen is added to the oxide semiconductor layer, heat treatment is performed on the oxide semiconductor layer to remove the impurities. In order to add oxygen, it is preferable to use a method in which oxygen having high energy is added by an ion implantation method, an ion doping method, or the like.

Claims

1. A method for manufacturing a semiconductor device, comprising the steps of:

forming an oxide semiconductor layer;

performing addition of oxygen on the oxide semiconductor layer; and

performing heat treatment at higher than or equal to 250°

C. and lower than or equal to 700°

C. on the oxide semiconductor layer on which the addition of oxygen is performed.

2. The method for manufacturing a semiconductor device, according to claim 1, further comprising the step of:

before forming the oxide semiconductor layer, forming an insulating film over a transistor,

wherein the oxide semiconductor layer is formed over the insulating film.

3. The method for manufacturing a semiconductor device, according to claim 1, wherein the addition of oxygen is performed by an ion implantation method.

4. The method for manufacturing a semiconductor device, according to claim 1, wherein the addition of oxygen is performed by an ion doping method.

5. The method for manufacturing a semiconductor device, according to claim 1, further comprising the step of:

before performing the addition of oxygen, performing a second heat treatment on the oxide semiconductor layer.

6. The method for manufacturing a semiconductor device, according to claim 1, wherein the oxide semiconductor layer comprises an In—

Ga—

Zn—

O based oxide semiconductor.

7. The method for manufacturing a semiconductor device, according to claim 1, wherein the oxide semiconductor layer is formed by a sputtering method using In₂O₃, Ga₂O₃, and ZnO.

8. A method for manufacturing a semiconductor device, comprising the steps of:

forming a gate electrode;

forming a gate insulating layer over the gate electrode;

forming an oxide semiconductor layer overlapping with the gate electrode so as to be in contact with the gate insulating layer;

performing addition of oxygen on the oxide semiconductor layer;

performing heat treatment on the oxide semiconductor layer on which the addition of oxygen is performed;

forming a source electrode and a drain electrode whose end portions overlap with the gate electrode so as to be in contact with the oxide semiconductor layer on which the heat treatment is performed; and

forming an insulating layer so as to be in contact with and overlap with a channel formation region of the oxide semiconductor layer.

9. The method for manufacturing a semiconductor device, according to claim 8, wherein the insulating layer is a silicon oxide layer formed by a sputtering method.

10. The method for manufacturing a semiconductor device, according to claim 8, further comprising the step of:

forming a silicon nitride layer over the insulating layer formed by a sputtering method,

wherein the insulating layer is a silicon oxide layer formed by a sputtering method.

11. The method for manufacturing a semiconductor device, according to claim 8, further comprising the step of:

before forming the oxide semiconductor layer, forming an insulating film over a transistor,

wherein the oxide semiconductor layer is formed over the insulating film.

12. The method for manufacturing a semiconductor device, according to claim 8, wherein the addition of oxygen is performed by an ion implantation method.

13. The method for manufacturing a semiconductor device, according to claim 8, wherein the addition of oxygen is performed by an ion doping method.

14. The method for manufacturing a semiconductor device, according to claim 8, further comprising the step of:

before performing the addition of oxygen, performing second heat treatment on the oxide semiconductor layer.

15. The method for manufacturing a semiconductor device, according to claim 8,

wherein the oxide semiconductor layer comprises an In—

Ga—

Zn—

O based oxide semiconductor, and

wherein the gate electrode comprises titanium.

16. The method for manufacturing a semiconductor device, according to claim 8, wherein the oxide semiconductor layer is formed by a sputtering method using In₂O₃, Ga₂O₃, and ZnO.

17. A method for manufacturing a semiconductor device, comprising the steps of:

forming a source electrode and a drain electrode;

forming an oxide semiconductor layer overlapping with an end portion of the source electrode and an end portion of the drain electrode;

performing addition of oxygen on the oxide semiconductor layer;

performing heat treatment on the oxide semiconductor layer on which the addition of oxygen is performed;

forming a gate insulating layer overlapping with the end portion of the source electrode and the end portion of the drain electrode to be in contact with the oxide semiconductor layer on which the heat treatment is performed; and

forming a gate electrode overlapping with the end portion of the source electrode and the end portion of the drain electrode so as to be in contact with the gate insulating layer.

18. The method for manufacturing a semiconductor device, according to claim 17, wherein the gate insulating layer is a silicon oxide layer formed by a sputtering method.

19. The method for manufacturing a semiconductor device, according to claim 17,

wherein the gate insulating layer is a stack of a silicon oxide layer and a silicon nitride layer over the silicon oxide layer, and

wherein the silicon oxide layer and the silicon nitride layer are formed by a sputtering method.

20. The method for manufacturing a semiconductor device, according to claim 17, further comprising the step of:

before forming the oxide semiconductor layer, forming an insulating film over a transistor,

wherein the oxide semiconductor layer is formed over the insulating film.

21. The method for manufacturing a semiconductor device, according to claim 17, wherein the addition of oxygen is performed by an ion implantation method.

22. The method for manufacturing a semiconductor device, according to claim 17, wherein the addition of oxygen is performed by an ion doping method.

23. The method for manufacturing a semiconductor device, according to claim 17, further comprising the step of:

before performing the addition of oxygen, performing second heat treatment on the oxide semiconductor layer.

24. The method for manufacturing a semiconductor device, according to claim 17,

wherein the oxide semiconductor layer comprises an In—

Ga—

Zn—

O based oxide semiconductor, and

wherein the gate electrode comprises titanium.

25. The method for manufacturing a semiconductor device, according to claim 17, wherein the oxide semiconductor layer is formed by a sputtering method using In₂O₃, Ga₂O₃, and ZnO.