SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SEMICONDUCTOR DEVICE

• US 20100233848A1
• Filed: 03/09/2010
• Published: 09/16/2010
• Est. Priority Date: 03/13/2009
• Status: Active Grant

• Current Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Original Assignee: Semiconductor Energy Laboratory Co., Ltd.
• Inventors: SASAKI, Toshinari, OHARA, Hiroki
• Granted Patent: US 8,936,963 B2
• Time in Patent Office: Days
• US Class Current: 438/104
• 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 21/02592 amorphous
• CPC Class Codes: H01L 21/02631 Physical deposition at reduced pressure, e.g. MBE, sputtering, evaporation
• CPC Class Codes: H01L 21/02667 Crystallisation or recrystallisation of non-monocrystalline semiconductor materials, e.g. regrowth
• 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 29/7869 having a semiconductor body comprising an oxide semiconductor material, e.g. zinc oxide, copper aluminium oxide, cadmium stannate

Abstract

If an oxide semiconductor layer is crystallized by heat treatment without being covered with an inorganic insulating film, surface unevenness and the like are formed due to the crystallization, which may cause variation in electrical characteristics. Steps are performed in the following order: a second insulating film is formed on an oxide semiconductor layer over a substrate and then heat treatment is performed, instead of performing heat treatment during a period immediately after formation of the oxide semiconductor layer and immediately before formation of an inorganic insulating film including silicon oxide on the oxide semiconductor layer. The density of hydrogen included in the inorganic insulating film including silicon oxide is 5×10²⁰/cm³ or more, and the density of nitrogen is 1×10¹⁹/cm³ or more.

Claims

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

forming an oxide semiconductor layer having an amorphous structure over a substrate having an insulating surface;

forming an inorganic insulating film including silicon oxide on the oxide semiconductor layer; and

performing heat treatment at 300°

C. or higher after the inorganic insulating film including silicon oxide is formed,

wherein the oxide semiconductor layer subjected to the heat treatment has an amorphous structure.

2. The method for manufacturing the semiconductor device according to claim 1, wherein the heat treatment is performed at a temperature higher than a substrate temperature at the time of forming the inorganic insulating film including silicon oxide.

3. The method for manufacturing the semiconductor device according to claim 1, wherein density of hydrogen included in the inorganic insulating film including silicon oxide is 5×

10²⁰/cm³ or more.

4. The method for manufacturing the semiconductor device according to claim 1, wherein density of nitrogen included in the inorganic insulating film including silicon oxide is 1×

10¹⁹/cm³ or more.

5. The method for manufacturing the semiconductor device according to claim 1, wherein the heat treatment is performed in an air atmosphere or in a nitrogen atmosphere.

6. The method for manufacturing the semiconductor device according to claim 1, wherein the inorganic insulating film including silicon oxide is formed using at least an N₂O gas.

7. The method for manufacturing the semiconductor device according to claim 1, wherein a substrate temperature at the time of forming the inorganic insulating film including silicon oxide on the oxide semiconductor layer is greater than or equal to 100°

C. and less than or equal to 300°

C.

8. The method for manufacturing the semiconductor device according to claim 1, wherein the oxide semiconductor layer includes at least one of indium, gallium, and zinc.

9. The method for manufacturing the semiconductor device according to claim 1, wherein the oxide semiconductor layer is a thin film represented by InMO₃(ZnO)_m (m>

0) wherein M denotes one or more of metal elements selected from Ga, Fe, Ni, Mn, or Co.

10. The method for manufacturing the semiconductor device according to claim 9, wherein M denotes Ga.

11. The method for manufacturing the semiconductor device according to claim 1, wherein a wiring is further formed on the inorganic insulating film including silicon oxide after the heat treatment.

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

forming a gate electrode over a substrate having an insulating surface;

forming a gate insulating layer over the gate electrode;

forming an oxide semiconductor layer having an amorphous structure over the gate insulating layer;

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

forming an inorganic insulating film including silicon oxide on the oxide semiconductor layer; and

performing heat treatment at greater than or equal to 300°

C. and less than or equal to a strain point of the substrate having the insulating surface after the inorganic insulating film including silicon oxide is formed.

13. The method for manufacturing the semiconductor device according to claim 12, wherein a substrate temperature at the time of forming the inorganic insulating film including silicon oxide is lower than a substrate temperature at the time of forming the gate insulating layer.

14. The method for manufacturing the semiconductor device according to claim 12, wherein the heat treatment is performed at a temperature higher than a substrate temperature at the time of forming the inorganic insulating film including silicon oxide, and the oxide semiconductor layer subjected to the heat treatment has an amorphous structure.

15. The method for manufacturing the semiconductor device according to claim 12, wherein density of hydrogen included in the inorganic insulating film including silicon oxide is 5×

10²⁰/cm³ or more.

16. The method for manufacturing the semiconductor device according to claim 12, wherein density of nitrogen included in the inorganic insulating film including silicon oxide is 1×

10¹⁹/cm³ or more.

17. The method for manufacturing the semiconductor device according to claim 12, wherein the heat treatment is performed in an air atmosphere or in a nitrogen atmosphere.

18. The method for manufacturing the semiconductor device according to claim 12, wherein the inorganic insulating film including silicon oxide is formed using at least an N₂O gas.

19. The method for manufacturing the semiconductor device according to claim 12, wherein the gate insulating layer is an inorganic insulating film including silicon oxide and formed using at least an N₂O gas.

20. The method for manufacturing the semiconductor device according to claim 12, wherein a substrate temperature at the time of forming the inorganic insulating film including silicon oxide on the oxide semiconductor layer is greater than or equal to 100°

C. and less than or equal to 300°

C.

21. The method for manufacturing the semiconductor device according to claim 12, wherein the oxide semiconductor layer includes at least one of indium, gallium, and zinc.

22. The method for manufacturing the semiconductor device according to claim 12, wherein the oxide semiconductor layer is a thin film represented by InMO₃(ZnO)_m (m>

0) wherein M denotes one or more of metal elements selected from Ga, Fe, Ni, Mn, or Co.

23. The method for manufacturing the semiconductor device according to claim 22, wherein M denotes Ga.

24. The method for manufacturing the semiconductor device according to claim 12, wherein a wiring is further formed on the inorganic insulating film including silicon oxide after the heat treatment.