Method for manufacturing semiconductor device

• US 9,054,137 B2
• Filed: 12/30/2013
• Issued: 06/09/2015
• Est. Priority Date: 06/30/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Sasaki, Toshinari, Sakata, Junichiro, Ohara, Hiroki, Yamazaki, Shunpei
• Primary Examiner(s): BACHNER, ROBERT G
• Application Number:
  US14/143,542
• Publication Number:
  US 20140113406A1
• Time in Patent Office: 526 Days
• Field of Search: 438/104, 438/151, 257/E21.411, 257/E21.459
• US Class Current: 1/1
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02664 Aftertreatments planarisation in general H01L21/304
• CPC Class Codes: H01L 21/383 using diffusion into or out of a solid from or into a gaseous phase
• CPC Class Codes: H01L 21/46 Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/428 manufacture of electrodes thereon H01L21/44
• CPC Class Codes: H01L 21/477 Thermal treatment for modifying the properties of semiconductor bodies, e.g. annealing, sintering H01L21/38 - H01L21/449 and H01L21/461 - H01L21/475 take precedence
• 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 29/66969 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

An object is to manufacture a highly reliable semiconductor device including a thin film transistor with stable electric characteristics. In a method for manufacturing a semiconductor device including a thin film transistor in which an oxide semiconductor film is used for a semiconductor layer including a channel formation region, heat treatment (for dehydration or dehydrogenation) is performed to improve the purity of the oxide semiconductor film and reduce impurities including moisture or the like. After that, slow cooling is performed under an oxygen atmosphere. Besides impurities including moisture or the like exiting in the oxide semiconductor film, heat treatment causes reduction of impurities including moisture or the like exiting in a gate insulating layer and those in interfaces between the oxide semiconductor film and films which are provided over and below the oxide semiconductor and in contact therewith.

Claims

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

forming an oxide semiconductor layer;

performing a heat treatment on the oxide semiconductor layer in a chamber, whereby a carrier concentration in the oxide semiconductor layer is higher than or equal to 1×

10¹⁸ cm<sup>−

3</sup>;

introducing oxygen into the chamber after the heat treatment; and

forming an insulating layer including oxygen over and in contact with a part of the oxide semiconductor layer, whereby a carrier concentration in the part of the oxide semiconductor layer is lower than 1×

10¹⁸ cm<sup>−

3</sup>,

wherein the heat treatment is performed under an inert atmosphere or under reduced pressure, and

wherein a hydrogen concentration in the oxide semiconductor layer is lower than 3×

10²⁰ cm<sup>−

3</sup> after the heat treatment.

2. The method for manufacturing a semiconductor device according to claim 1, wherein the inert atmosphere is a nitrogen atmosphere or a rare gas atmosphere.

3. The method for manufacturing a semiconductor device according to claim 1, further comprising the step of forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer.

4. The method for manufacturing a semiconductor device according to claim 1, wherein the heat treatment is performed at a temperature higher than or equal to 400°

C.

5. The method for manufacturing a semiconductor device according to claim 1, wherein the oxide semiconductor layer includes a crystal.

6. The method for manufacturing a semiconductor device according to claim 1, wherein the oxide semiconductor layer comprises indium and zinc.

7. The method for manufacturing a semiconductor device according to claim 1, wherein the oxide semiconductor layer comprises a material selected from the group consisting of In—

Sn—

Zn—

O-based oxide semiconductor;

an In—

Al—

Zn—

O-based oxide semiconductor;

a Sn—

Ga—

Zn—

O-based oxide semiconductor;

an Al—

Ga—

Zn—

O-based oxide semiconductor;

a Sn—

Al—

Zn—

O-based oxide semiconductor;

an In—

Zn—

O-based oxide semiconductor;

an In—

Ga—

O-based oxide semiconductor;

a Sn—

Zn—

O-based oxide semiconductor;

an Al—

Zn—

O-based oxide semiconductor;

an In—

O-based oxide semiconductor;

a Sn—

O-based oxide semiconductor; and

a Zn—

O-based oxide semiconductor.

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

forming an oxide semiconductor layer;

performing a heat treatment on the oxide semiconductor layer in a chamber, whereby the oxide semiconductor layer comprises an oxide semiconductor in an oxygen-deficiency state;

introducing oxygen into the chamber after the heat treatment; and

forming an insulating layer including oxygen over and in contact with a part of the oxide semiconductor layer, whereby the part of the oxide semiconductor layer comprises an oxide semiconductor in an oxygen-excess state,

wherein the heat treatment is performed under an inert atmosphere or under reduced pressure, and

wherein a hydrogen concentration in the oxide semiconductor layer is lower than 3×

10²⁰ cm<sup>−

3</sup> after the heat treatment.

9. The method for manufacturing a semiconductor device according to claim 8, wherein the inert atmosphere is a nitrogen atmosphere or a rare gas atmosphere.

10. The method for manufacturing a semiconductor device according to claim 8, further comprising the step of forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer.

11. The method for manufacturing a semiconductor device according to claim 8, wherein the heat treatment is performed at a temperature higher than or equal to 400°

C.

12. The method for manufacturing a semiconductor device according to claim 8, wherein the oxide semiconductor layer includes a crystal.

13. The method for manufacturing a semiconductor device according to claim 8, wherein the oxide semiconductor layer comprises indium and zinc.

14. The method for manufacturing a semiconductor device according to claim 8, wherein the oxide semiconductor layer comprises a material selected from the group consisting of In—

Sn—

Zn—

O-based oxide semiconductor;

an In—

Al—

Zn—

O-based oxide semiconductor;

a Sn—

Ga—

Zn—

O-based oxide semiconductor;

an Al—

Ga—

Zn—

O-based oxide semiconductor;

a Sn—

Al—

Zn—

O-based oxide semiconductor;

an In—

Zn—

O-based oxide semiconductor;

an In—

Ga—

O-based oxide semiconductor;

a Sn—

Zn—

O-based oxide semiconductor;

an Al—

Zn—

O-based oxide semiconductor;

an In—

O-based oxide semiconductor;

a Sn—

O-based oxide semiconductor; and

a Zn—

O-based oxide semiconductor.

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

forming an oxide semiconductor layer;

performing dehydration or dehydrogenation on the oxide semiconductor layer in a chamber, whereby the oxide semiconductor layer comprises an n-type oxide semiconductor;

introducing oxygen into the chamber after the dehydration or the dehydrogenation; and

forming an oxide insulating layer over and in contact with the oxide semiconductor layer, whereby the oxide semiconductor layer comprises an i-type oxide semiconductor,

wherein the dehydration or the dehydrogenation is performed under an inert atmosphere or under reduced pressure, and

wherein a hydrogen concentration in the oxide semiconductor layer is lower than 3×

10²⁰ cm<sup>−

3</sup> after the dehydration or the dehydrogenation.

16. The method for manufacturing a semiconductor device according to claim 15, wherein the inert atmosphere is a nitrogen atmosphere or a rare gas atmosphere.

17. The method for manufacturing a semiconductor device according to claim 15, further comprising the step of forming a source electrode layer and a drain electrode layer over the oxide semiconductor layer.

18. The method for manufacturing a semiconductor device according to claim 15, wherein the dehydration or the dehydrogenation is performed at a temperature higher than or equal to 400°

C.

19. The method for manufacturing a semiconductor device according to claim 15, wherein the oxide semiconductor layer includes a crystal.

20. The method for manufacturing a semiconductor device according to claim 15, wherein the oxide semiconductor layer comprises indium and zinc.

21. The method for manufacturing a semiconductor device according to claim 15, wherein the oxide semiconductor layer comprises a material selected from the group consisting of In—

Sn—

Zn—

O-based oxide semiconductor;

an In—

Al—

Zn—

O-based oxide semiconductor;

a Sn—

Ga—

Zn—

O-based oxide semiconductor;

an Al—

Ga—

Zn—

O-based oxide semiconductor;

a Sn—

Al—

Zn—

O-based oxide semiconductor;

an In—

Zn—

O-based oxide semiconductor;

an In—

Ga—

O-based oxide semiconductor;

a Sn—

Zn—

O-based oxide semiconductor;

an Al—

Zn—

O-based oxide semiconductor;

an In—

O-based oxide semiconductor;

a Sn—

O-based oxide semiconductor; and

a Zn—

O-based oxide semiconductor.