Method for manufacturing semiconductor device

• US 8,623,698 B2
• Filed: 03/04/2013
• Issued: 01/07/2014
• 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): Maldonado, Julio J
• Assistant Examiner(s): BACHNER, ROBERT G
• Application Number:
  US13/783,672
• Publication Number:
  US 20130178015A1
• Time in Patent Office: 309 Days
• Field of Search: 257/E21.411, 257/E21.459, 438/151
• US Class Current: 438/104
• 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 first heat treatment on the oxide semiconductor layer to reduce a hydrogen concentration of the oxide semiconductor layer in an inert atmosphere in a chamber;

after the first heat treatment, introducing oxygen into the chamber in order to supply oxygen to the oxide semiconductor layer in the chamber; and

forming an oxide insulating film in contact with the oxide semiconductor layer.

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

3. The method for manufacturing a semiconductor device according to claim 1, further comprising the step of cooling the oxide semiconductor layer during the step of introducing oxygen into the chamber.

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

5. The method for manufacturing a semiconductor device according to claim 1, wherein the first heat treatment is performed by using a gas rapid thermal annealing method or a lamp rapid thermal annealing method.

6. The method for manufacturing a semiconductor device according to claim 1, further comprising a step of performing a second heat treatment after forming the oxide insulating film.

7. The method for manufacturing a semiconductor device according to claim 1, wherein carrier concentration of a portion of the oxide semiconductor layer which is in contact with the oxide insulating film is less than or equal to 1×

10¹⁴/cm³.

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

forming an oxide semiconductor layer;

performing a first heat treatment on the oxide semiconductor layer to reduce a hydrogen concentration of the oxide semiconductor layer under reduced pressure in a chamber;

after the first heat treatment, introducing oxygen into the chamber in order to supply oxygen to the oxide semiconductor layer in the chamber; and

forming an oxide insulating film in contact with the oxide semiconductor layer.

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

10. The method for manufacturing a semiconductor device according to claim 8, further comprising the step of cooling the oxide semiconductor layer during the step of introducing oxygen into the chamber.

11. The method for manufacturing a semiconductor device according to claim 8, wherein the first heat treatment is performed by using a gas rapid thermal annealing method or a lamp rapid thermal annealing method.

12. The method for manufacturing a semiconductor device according to claim 8, further comprising a step of performing a second heat treatment after forming the oxide insulating film.

13. The method for manufacturing a semiconductor device according to claim 8, wherein carrier concentration of a portion of the oxide semiconductor layer which is in contact with the oxide insulating film is less than or equal to 1×

10¹⁴/cm³.

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

forming a gate electrode over a substrate;

forming a gate insulating layer over the gate electrode;

forming an oxide semiconductor layer over the gate insulating layer;

performing a first heat treatment on the oxide semiconductor layer in a chamber;

after the first heat treatment, introducing oxygen into the chamber in order to supply oxygen to the oxide semiconductor layer in the chamber;

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

forming an oxide insulating film in contact with the oxide semiconductor layer,

wherein the first heat treatment is performed at a first temperature higher or equal to 400°

C.

15. The method for manufacturing a semiconductor device according to claim 14, wherein the oxide semiconductor layer includes indium, gallium and zinc.

16. The method for manufacturing a semiconductor device according to claim 14, wherein a hydrogen concentration of the oxide semiconductor layer is reduced by the first heat treatment.

17. The method for manufacturing a semiconductor device according to claim 14, wherein the first heat treatment is performed under reduced pressure.

18. The method for manufacturing a semiconductor device according to claim 14, wherein the first heat treatment is performed in an inert atmosphere.

19. The method for manufacturing a semiconductor device according to claim 14, wherein the first heat treatment is performed by using a gas rapid thermal annealing method or a lamp rapid thermal annealing method.

20. The method for manufacturing a semiconductor device according to claim 14, further comprising a step of performing a second heat treatment after forming the oxide insulating film.

21. The method for manufacturing a semiconductor device according to claim 14, wherein carrier concentration of a portion of the oxide semiconductor layer which is in contact with the oxide insulating film is less than or equal to 1×

10¹⁴/cm³.

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

forming an insulating film over the oxide insulating film; and

forming a pixel electrode over the insulating film,

wherein the pixel electrode is electrically connected to one of the source electrode and the drain electrode.

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

forming a gate electrode over a substrate;

forming a gate insulating layer over the gate electrode;

forming an oxide semiconductor layer over the gate insulating layer;

performing a first heat treatment on the oxide semiconductor layer in a chamber;

after the first heat treatment, introducing oxygen into the chamber in order to supply oxygen to the oxide semiconductor layer in the chamber;

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

forming an oxide insulating film in contact with the oxide semiconductor layer,

wherein after the first heat treatment, the oxide semiconductor layer includes crystals.

24. The method for manufacturing a semiconductor device according to claim 23, wherein the oxide semiconductor layer includes indium, gallium and zinc.

25. The method for manufacturing a semiconductor device according to claim 23, wherein a hydrogen concentration of the oxide semiconductor layer is reduced by the first heat treatment.

26. The method for manufacturing a semiconductor device according to claim 23, wherein the first heat treatment is performed under reduced pressure.

27. The method for manufacturing a semiconductor device according to claim 23, wherein the first heat treatment is performed in an inert atmosphere.

28. The method for manufacturing a semiconductor device according to claim 23, wherein the first heat treatment is performed by using a gas rapid thermal annealing method or a lamp rapid thermal annealing method.

29. The method for manufacturing a semiconductor device according to claim 23, further comprising a step of performing a second heat treatment after forming the oxide insulating film.

30. The method for manufacturing a semiconductor device according to claim 23, wherein carrier concentration of a portion of the oxide semiconductor layer which is in contact with the oxide insulating film is less than or equal to 1×

10¹⁴/cm³.

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

forming an insulating film over the oxide insulating film; and

forming a pixel electrode over the insulating film,

wherein the pixel electrode is electrically connected to one of the source electrode and the drain electrode.