SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME

• US 20140030845A1
• Filed: 07/18/2013
• Published: 01/30/2014
• Est. Priority Date: 07/26/2012
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: KOEZUKA, Junichi, SASAKI, Toshinari, YAMAZAKI, Shunpei
• Granted Patent: US 9,748,355 B2
• Time in Patent Office: Days
• US Class Current: 438/104
• CPC Class Codes: H01L 29/66477 with an insulated gate, i.e. MISFET
• 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

The amount of nitrogen that is transferred to an oxide semiconductor film of a transistor including the oxide semiconductor film is reduced. In addition, in a semiconductor device which includes a transistor including an oxide semiconductor film, change in electrical characteristics is suppressed and reliability is improved. After a nitrogen-containing oxide insulating film is formed over a transistor including an oxide semiconductor film where a channel region is formed, nitrogen is released from the nitrogen-containing oxide insulating film by heat treatment. Note that the nitrogen concentration which is obtained by secondary ion mass spectrometry (SIMS) is greater than or equal to the lower limit of detection by SIMS and less than 3×10²⁰ atoms/cm³.

Claims

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

forming a gate electrode over a substrate;

forming a gate insulating film over the gate electrode;

forming an oxide semiconductor film over the gate insulating film;

performing a first heat treatment on the substrate;

forming a nitrogen-containing oxide insulating film over the oxide semiconductor film; and

releasing nitrogen from the nitrogen-containing oxide insulating film by a second heat treatment,

wherein a nitrogen concentration of the nitrogen-containing oxide insulating film is greater than or equal to a lower limit of detection by SIMS and less than 3×

10²⁰ atoms/cm³, and

wherein a spin density of a signal which appears when g is 1.93, due to defects in the oxide semiconductor film, is lower than or equal to 1×

10¹⁷ spins/cm³.

2. The method for manufacturing a semiconductor device, according to claim 1, wherein a temperature of the second heat treatment is higher than or equal to 150°

C. and lower than or equal to 500°

C.

3. The method for manufacturing a semiconductor device, according to claim 1, wherein the nitrogen-containing oxide insulating film is a nitrogen-containing silicon oxide film.

4. The method for manufacturing a semiconductor device, according to claim 1, wherein the oxide semiconductor film comprises In, Ga, and Zn.

5. The method for manufacturing a semiconductor device, according to claim 1, wherein the oxide semiconductor film is a c-axis aligned crystalline oxide semiconductor film including crystallized parts.

6. The method for manufacturing a semiconductor device, according to claim 1, wherein a nitrogen concentration of the oxide semiconductor film is less than or equal to 5×

10¹⁸ atoms/cm³.

7. The method for manufacturing a semiconductor device, according to claim 1, wherein the first heat treatment is performed first in an atmosphere of an inert gas and then in an oxygen atmosphere.

8. The method for manufacturing a semiconductor device, according to claim 1, wherein the nitrogen-containing oxide insulating film is formed by a plasma CVD method using a deposition gas containing silicon and a dinitrogen monoxide gas or a nitrogen dioxide gas.

9. The method for manufacturing a semiconductor device, according to claim 1, further comprising a step of forming a pair of electrodes before forming the nitrogen-containing oxide insulating film.

10. The method for manufacturing a semiconductor device, according to claim 9, further comprising a step of performing a plasma treatment after forming the pair of electrodes.

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

forming a gate electrode over a substrate;

forming a gate insulating film over the gate electrode;

forming an oxide semiconductor film over the gate insulating film;

performing a first heat treatment on the substrate;

forming a nitrogen-containing oxide insulating film over the oxide semiconductor film; and

releasing nitrogen from the nitrogen-containing oxide insulating film by a second heat treatment,

wherein a nitrogen concentration of the nitrogen-containing oxide insulating film is greater than or equal to a lower limit of detection by SIMS and less than 3×

10²⁰ atoms/cm³, and

wherein the step of forming the oxide semiconductor film is performed by a sputtering method using a polycrystalline oxide semiconductor sputtering target.

12. The method for manufacturing a semiconductor device, according to claim 11, wherein a temperature of the second heat treatment is higher than or equal to 150°

C. and lower than or equal to 500°

C.

13. The method for manufacturing a semiconductor device, according to claim 11, wherein the nitrogen-containing oxide insulating film is a nitrogen-containing silicon oxide film.

14. The method for manufacturing a semiconductor device, according to claim 11, wherein the oxide semiconductor film comprises In, Ga, and Zn.

15. The method for manufacturing a semiconductor device, according to claim 11, wherein the oxide semiconductor film is a c-axis aligned crystalline oxide semiconductor film including crystallized parts.

16. The method for manufacturing a semiconductor device, according to claim 11, wherein a nitrogen concentration of the oxide semiconductor film is less than or equal to 5×

10¹⁸ atoms/cm³.

17. The method for manufacturing a semiconductor device, according to claim 11, wherein the first heat treatment is performed first in an atmosphere of an inert gas and then in an oxygen atmosphere.

18. The method for manufacturing a semiconductor device, according to claim 11, wherein the nitrogen-containing oxide insulating film is formed by a plasma CVD method using a deposition gas containing silicon and a dinitrogen monoxide gas or a nitrogen dioxide gas.

19. The method for manufacturing a semiconductor device, according to claim 11, further comprising a step of forming a pair of electrodes before forming the nitrogen-containing oxide insulating film.

20. The method for manufacturing a semiconductor device, according to claim 19, further comprising a step of performing a plasma treatment after forming the pair of electrodes.