Semiconductor device and method for manufacturing the same

• US 8,785,265 B2
• Filed: 11/26/2013
• Issued: 07/22/2014
• Est. Priority Date: 11/30/2010
• Status: Expired due to Fees

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: Yamazaki, Shunpei
• Primary Examiner(s): Lee, Calvin
• Application Number:
  US14/089,986
• Publication Number:
  US 20140087516A1
• Time in Patent Office: 238 Days
• Field of Search: 257/43, 257/57, 257/325, 257/335, 438/104, 438/158, 438/162
• US Class Current: 438/162
• CPC Class Codes: H01L 21/02422 Non-crystalline insulating materials, e.g. glass, polymers
• CPC Class Codes: H01L 21/02472 Oxides
• CPC Class Codes: H01L 21/02483 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• 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 21/02658 Pretreatments cleaning in general H01L21/02041
• 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

Abstract

An object to provide a material suitably used for used for a semiconductor included in a transistor, a diode, or the like, with the use of a sputtering method. Specifically, an object is to provide a manufacturing process an oxide semiconductor film having high crystallinity. By intentionally adding nitrogen to the oxide semiconductor, an oxide semiconductor film having a wurtzite crystal structure that is a hexagonal crystal structure is formed. In the oxide semiconductor film, the crystallinity of a region containing nitrogen is higher than that of a region hardly containing nitrogen or a region to which nitrogen is not intentionally added. The oxide semiconductor film having high crystallinity and having a wurtzite crystal structure is used as a channel formation region of a transistor.

Claims

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

forming an insulating film containing nitrogen over a substrate including an insulating surface;

introducing the substrate over which the insulating film containing nitrogen is formed, into a vacuum chamber;

forming a first oxide semiconductor film containing nitrogen by sputtering in a nitrogen containing atmosphere under a first deposition condition that the substrate temperature is higher than or equal to 150°

C. and lower than or equal to 450°

C.;

forming a second oxide semiconductor film containing nitrogen by sputtering in a nitrogen containing atmosphere under a second deposition condition that the substrate temperature is higher than or equal to 150°

C. and lower than or equal to 450°

C.; and

performing heat treatment at a temperature higher than or equal to 150°

C. and lower than or equal to 650°

C. after the deposition is performed under the second deposition condition,

wherein the first oxide semiconductor film to which the heat treatment is performed has a wurtzite crystal structure.

2. The method for manufacturing a semiconductor device according to claim 1, wherein a percentage of a flow rate of a nitrogen gas with respect to a total flow rate of a sputtering gas under the first deposition condition is different from a percentage of a flow rate of a nitrogen gas with respect to a total flow rate of a sputtering gas under the second deposition condition.

3. The method for manufacturing a semiconductor device according to claim 1, wherein a percentage of a flow rate of a nitrogen gas with respect to a total flow rate of a sputtering gas which is introduced into the vacuum chamber is greater than or equal to 90% and less than or equal to 100% under the first deposition condition.

4. The method for manufacturing a semiconductor device according to claim 1, wherein a nitrogen gas is introduced into the vacuum chamber while the nitrogen gas is heated under the first deposition condition.

5. The method for manufacturing a semiconductor device according to claim 1, wherein a sputtering gas which includes an oxygen gas or a rare gas besides the nitrogen gas is introduced under the second deposition condition.

6. The method for manufacturing a semiconductor device according to claim 1, further comprising the step of performing nitrogen plasma treatment on a surface of the insulating film containing nitrogen after the insulating film containing nitrogen is formed.

7. The method for manufacturing a semiconductor device according to claim 1, wherein the insulating film containing nitrogen is formed by nitrogen plasma treatment on a surface of an insulating film.

8. The method for manufacturing a semiconductor device according to claim 1, wherein the second oxide semiconductor film to which the heat treatment is performed has a wurtzite crystal structure.

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

forming a gate electrode layer over a substrate including an insulating surface;

forming an insulating film containing nitrogen over the gate electrode layer;

introducing the substrate over which the gate electrode layer and the insulating film containing nitrogen are formed, into a vacuum chamber;

forming a first oxide semiconductor film containing nitrogen by sputtering in a nitrogen containing atmosphere under a first deposition condition that the substrate temperature is higher than or equal to 150°

C. and lower than or equal to 450°

C.;

forming a second oxide semiconductor film containing nitrogen by sputtering in a nitrogen containing atmosphere under a second deposition condition that the substrate temperature is higher than or equal to 150°

C. and lower than or equal to 450°

C.; and

performing heat treatment at a temperature higher than or equal to 150°

C. and lower than or equal to 650°

C. after the deposition is performed under the second deposition condition,

wherein the first oxide semiconductor film to which the heat treatment is performed has a wurtzite crystal structure.

10. The method for manufacturing a semiconductor device according to claim 9, wherein a percentage of a flow rate of a nitrogen gas with respect to a total flow rate of a sputtering gas under the first deposition condition is greater than a percentage of a flow rate of a nitrogen gas with respect to a total flow rate of a sputtering gas under the second deposition condition.

11. The method for manufacturing a semiconductor device according to claim 9, wherein a percentage of a flow rate of a nitrogen gas with respect to a total flow rate of a sputtering gas which is introduced into the vacuum chamber is greater than or equal to 90% and less than or equal to 100% under the first deposition condition.

12. The method for manufacturing a semiconductor device according to claim 9, wherein a nitrogen gas is introduced into the vacuum chamber while the nitrogen gas is heated under the first deposition condition.

13. The method for manufacturing a semiconductor device according to claim 9, wherein a sputtering gas which includes an oxygen gas or a rare gas besides the nitrogen gas is introduced under the second deposition condition.

14. The method for manufacturing a semiconductor device according to claim 9, further comprising the step of performing nitrogen plasma treatment on a surface of the insulating film containing nitrogen after the insulating film containing nitrogen is formed.

15. The method for manufacturing a semiconductor device according to claim 9, wherein the insulating film containing nitrogen is formed by nitrogen plasma treatment on a surface of the insulating film.

16. The method for manufacturing a semiconductor device according to claim 9, wherein the second oxide semiconductor film to which the heat treatment is performed has a wurtzite crystal structure.