Semiconductor device and method for manufacturing semiconductor device

• US 10,243,081 B2
• Filed: 03/21/2016
• Issued: 03/26/2019
• Est. Priority Date: 01/25/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei, Koezuka, Junichi, Okazaki, Kenichi, Ikeyama, Terumasa, Tochibayashi, Katsuaki
• Primary Examiner(s): Galvin, III, Joseph
• Application Number:
  US15/075,775
• Publication Number:
  US 20160284855A1
• Time in Patent Office: 1,100 Days
• CPC Class Codes: H01L 21/385 using diffusion into or out of a solid from or into a solid phase, e.g. a doped oxide layer
• CPC Class Codes: H01L 29/045 by their particular orientation of crystalline planes
• CPC Class Codes: H01L 29/4908 for thin film semiconductor, e.g. gate of TFT
• 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 29/78606 with supplementary region or layer in the thin film or in the insulated bulk substrate supporting it for controlling or increasing the safety of the device H01L29/78642, H01L29/78645 take precedence
• 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

A highly reliable semiconductor device including a transistor using an oxide semiconductor is provided. In a semiconductor device including a bottom-gate transistor including an oxide semiconductor layer, a first insulating layer is formed in contact with the oxide semiconductor layer, and an oxygen doping treatment is performed thereon, whereby the first insulating layer is made to contain oxygen in excess of the stoichiometric composition. The formation of the second insulating layer over the first insulating layer enables excess oxygen included in the first insulating layer to be supplied efficiently to the oxide semiconductor layer. Accordingly, the highly reliable semiconductor device with stable electric characteristics can be provided.

Claims

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

forming an oxide semiconductor layer containing In and Ga at a proportion of In>

Ga;

etching a part of the oxide semiconductor layer by a wet etching method;

forming a silicon oxynitride film over the oxide semiconductor layer; and

introducing oxygen to the silicon oxynitride film by a plasma treatment under an oxygen atmosphere,

wherein a copper concentration in the oxide semiconductor layer is less than or equal to 1×

10¹⁸ atoms/cm³.

2. The method for manufacturing the semiconductor device according to claim 1,

wherein part of oxygen introduced into the silicon oxynitride film is introduced into the oxide semiconductor layer through the silicon oxynitride film.

3. The method for manufacturing the semiconductor device according to claim 1,

wherein the oxide semiconductor layer contains In, Ga, and Zn with an atomic ratio of In:

Ga;

Zn=3/6;

1/6;

2/6 or in the neighborhood of In;

Ga;

Zn=3/6;

1/6;

2/6, and

wherein an oxide semiconductor layer with an atomic ratio of In;

Ga;

Zn=A;

B;

C (A+B+C=1) and satisfying (3/6−

A)²+(1/6−

B)²+(2/6−

C)²≤

0.0025 is in the neighborhood of In;

Ga;

Zn=3/6;

1/6;

2/6.

4. The method for manufacturing the semiconductor device according to claim 1,

wherein the oxide semiconductor layer contains In, Ga, and Zn with an atomic ratio of In:

Ga;

Zn=2/6;

1/6;

3/6 or in the neighborhood of In;

Ga;

Zn=2/6;

1/6;

3/6, and

wherein an oxide semiconductor layer with an atomic ratio of In;

Ga;

Zn=A;

B;

C (A+B+C=1) and satisfying (2/6−

A)²+(1/6−

B)²+(3/6−

C)²≤

0.0025 is in the neighborhood of In;

Ga;

Zn=2/6;

1/6;

3/6.

5. The method for manufacturing the semiconductor device according to claim 1,

wherein the oxide semiconductor layer contains In and Ga at a proportion of In>

2 Ga.

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

forming a gate electrode with a stacked-layer structure including a first layer comprising a light-transmitting conductive material and a second layer comprising a metal element.

7. The method for manufacturing the semiconductor device according to claim 1,

wherein a hydrogen concentration in the silicon oxynitride film is less than 7.2×

10²⁰ atoms/cm³.

8. The method for manufacturing the semiconductor device according to claim 1,

wherein c-axes are aligned, and a-axes or b-axes are not macroscopically aligned in the oxide semiconductor layer.

9. The method for manufacturing the semiconductor device according to claim 1,

wherein the oxide semiconductor layer includes microcrystal with a size greater than or equal to 1 nm and less than 10 nm.

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

forming a gate electrode;

forming an insulating layer over the gate electrode;

forming an oxide semiconductor layer over the insulating layer, the oxide semiconductor layer containing In and Ga at a proportion of In>

Ga;

etching the oxide semiconductor layer by a wet etching method;

forming a silicon oxynitride film over the oxide semiconductor layer; and

introducing oxygen to the silicon oxynitride film by a plasma treatment under an oxygen atmosphere,

wherein a copper concentration in the oxide semiconductor layer is less than or equal to 1×

10¹⁸ atoms/cm³.

11. The method for manufacturing the semiconductor device according to claim 10,

wherein part of oxygen introduced into the silicon oxynitride film is introduced into the oxide semiconductor layer through the silicon oxynitride film.

12. The method for manufacturing the semiconductor device according to claim 10,

wherein the oxide semiconductor layer contains In, Ga, and Zn with an atomic ratio of In:

Ga;

Zn=3/6;

1/6;

2/6 or in the neighborhood of In;

Ga;

Zn=3/6;

1/6;

2/6, and

wherein an oxide semiconductor layer with an atomic ratio of In;

Ga;

Zn=A;

B;

C (A+B+C=1) and satisfying (3/6−

A)²+(1/6−

B)²+(2/6−

C)²≤

0.0025 is in the neighborhood of In;

Ga;

Zn=3/6;

1/6;

2/6.

13. The method for manufacturing the semiconductor device according to claim 10,

wherein the oxide semiconductor layer contains In, Ga, and Zn with an atomic ratio of In:

Ga;

Zn=2/6;

1/6;

3/6 or in the neighborhood of In;

Ga;

Zn=2/6;

1/6;

3/6, and

wherein an oxide semiconductor layer with an atomic ratio of In;

Ga;

Zn=A;

B;

C (A+B+C=1) and satisfying (2/6−

A)²+(1/6−

B)²+(3/6−

C)²≤

0.0025 is in the neighborhood of In;

Ga;

Zn=2/6;

1/6;

3/6.

14. The method for manufacturing the semiconductor device according to claim 10,

wherein the oxide semiconductor layer contains In and Ga at a proportion of In>

2 Ga.

15. The method for manufacturing the semiconductor device according to claim 10,

wherein the gate electrode is a stacked-layer structure including a first layer comprising a light-transmitting conductive material and a second layer comprising a metal element.

16. The method for manufacturing the semiconductor device according to claim 10,

wherein a hydrogen concentration in the silicon oxynitride film is less than 7.2×

10²⁰ atoms/cm³.

17. The method for manufacturing the semiconductor device according to claim 10,

wherein c-axes are aligned, and a-axes and/or b-axes are not macroscopically aligned in the oxide semiconductor layer.

18. The method for manufacturing the semiconductor device according to claim 10,

wherein the oxide semiconductor layer includes microcrystal (also referred to as nanocrystal) with a size greater than or equal to 1 nm and less than 10 nm.

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

forming an oxide semiconductor layer containing In and Ga at a proportion of In>

Ga;

etching a part of the oxide semiconductor layer by a wet etching method;

forming a source electrode and a drain electrode over the oxide semiconductor layer;

forming a silicon oxynitride film over the source electrode and the drain electrode; and

introducing oxygen to the silicon oxynitride film by a plasma treatment under an oxygen atmosphere,

wherein a copper concentration in the oxide semiconductor layer is less than or equal to 1×

10¹⁸ atoms/cm³.

20. The method for manufacturing the semiconductor device according to claim 19,

wherein part of oxygen introduced into the silicon oxynitride film is introduced into the oxide semiconductor layer through the silicon oxynitride film.

21. The method for manufacturing the semiconductor device according to claim 19,

wherein the oxide semiconductor layer contains In, Ga, and Zn with an atomic ratio of In:

Ga;

Zn=3/6;

1/6;

2/6 or in the neighborhood of In;

Ga;

Zn=3/6;

1/6;

2/6, and

wherein an oxide semiconductor layer with an atomic ratio of In;

Ga;

Zn=A;

B;

C (A+B+C=1) and satisfying (3/6−

A)²+(1/6−

B)²+(2/6−

C)²≤

0.0025 is in the neighborhood of In;

Ga;

Zn=3/6;

1/6;

2/6.

22. The method for manufacturing the semiconductor device according to claim 19,

wherein the oxide semiconductor layer contains In, Ga, and Zn with an atomic ratio of In:

Ga;

Zn=2/6;

1/6;

3/6 or in the neighborhood of In;

Ga;

Zn=2/6;

1/6;

3/6, and

wherein an oxide semiconductor layer with an atomic ratio of In;

Ga;

Zn=A;

B;

C (A+B+C=1) and satisfying (2/6−

A)²+(1/6−

B)²+(3/6−

C)²≤

0.0025 is in the neighborhood of In;

Ga;

Zn=2/6;

1/6;

3/6.

23. The method for manufacturing the semiconductor device according to claim 19,

wherein the oxide semiconductor layer contains In and Ga at a proportion of In>

2 Ga.

24. The method for manufacturing the semiconductor device according to claim 19, further comprising a step of:

forming a gate electrode with a stacked-layer structure including a first layer comprising a light-transmitting conductive material and a second layer comprising a metal element.

25. The method for manufacturing the semiconductor device according to claim 19,

wherein a hydrogen concentration in the silicon oxynitride film is less than 7.2×

10²⁰ atoms/cm³.

26. The method for manufacturing the semiconductor device according to claim 19,

wherein c-axes are aligned, and a-axes or b-axes are not macroscopically aligned in the oxide semiconductor layer.

27. The method for manufacturing the semiconductor device according to claim 19,

wherein the oxide semiconductor layer includes microcrystal with a size greater than or equal to 1 nm and less than 10 nm.