Dielectric film and method of forming it, semiconductor device, non-volatile semiconductor memory device, and production method for semiconductor device
View Patent ↗In a film formation method of a semiconductor device including a plurality of silicon-based transistors or capacitors, there exist hydrogen at least in a part of the silicon surface in advance, and the film formation method removes the hydrogen by exposing the silicon surface to a first inert gas plasma. Thereafter a silicon compound layer is formed on the surface of the silicon gas by generating plasma while using a mixed gas of a second inert gas and one or more gaseous molecules, such that there is formed a silicon compound layer containing at least a pat of the elements constituting the gaseous molecules, on the surface of the silicon gas.
1. A method of forming a dielectric film, comprising:
removing surface-terminated hydrogens from a surface by exposing the surface to a high-density Kr plasma or to low energy Ar ions;
forming a silicon oxide film on the surface; and
modifying a surface of said silicon oxide film by exposing the same to hydrogen nitride radicals NH* in the absence of a Si-containing gas.
2. The method of forming a dielectric film as claimed in claim 1 , wherein said hydrogen nitride radicals NH* are formed by a microwave plasma formed in a mixed gas of an inert gas selected from the group consisting of Ar and Kr and a gas containing nitrogen and hydrogen.
3. The method of forming a dielectric film as claimed in claim 2 , wherein said microwave plasma has an electron density of 10 12 cm −2 or more at said surface.
4. The method of forming a dielectric film as claimed in claim 2 , wherein said microwave plasma has a plasma potential of 10V or less at said surface.
5. The method of forming a dielectric film as claimed in claim 2 , wherein said gas containing nitrogen and hydrogen comprises an NH 3 gas.
6. The method of forming a dielectric film as claimed in claim 1 , wherein said surface comprises a silicon surface and said oxide film is formed by oxidation of said silicon surface.
7. The method of forming a dielectric film as claimed in claim 6 , wherein said oxidation of said silicon surface is conducted by exposing said silicon surface to microwave plasma formed in a mixed gas of an inert gas predominantly of Kr and a gas containing oxygen as a constituent element.
8. The method of forming a dielectric film as claimed in claim 6 , wherein said silicon oxide film is formed by thermal oxidation of said surface.
9. A method of forming a dielectric film, comprising:
removing surface-terminated hydrogens from a surface by exposing the surface to a high-density Kr plasma or to low energy Ar ions;
forming a silicon oxide film on the surface; and
modifying a surface of said silicon oxide film by exposing the same to microwave plasma formed in a mixed gas of an inert gas selected from the group consisting of Ar and Kr and a gas containing nitrogen and hydrogen in the absence of a Si-containing gas.
10. The method of forming a dielectric film as claimed in claim 9 , wherein said microwave plasma has an electron density of 10 12 cm −3 or more at said surface.
11. The method of forming a dielectric film as claimed in claim 9 , wherein said microwave plasma has a plasma potential of 10V or less at said surface.
12. The method of forming a dielectric film as claimed in claim 9 , wherein said gas containing said nitrogen and hydrogen as constituent elements comprises a NH 3 gas.
13. The method of forming a dielectric film as claimed in claim 9 , wherein said surface comprises a silicon surface and wherein said oxide film is formed by oxidation of said silicon surface.
14. The method of forming a dielectric film as claimed in claim 13 , wherein said oxidation of said silicon surface is conducted by exposing said silicon surface to a microwave plasma formed in a mixed gas of an inert gas predominantly of Kr and a gas containing oxygen.
15. The method of forming a dielectric film as claimed in claim 13 , wherein said silicon oxide film is formed by thermal oxidation of said silicon surface.
16. A method of forming a dielectric film comprising
exposing a silicon surface to a high-density Kr plasma or to low energy Ar ions in order to remove surface-terminated hydrogens from the silicon surface to form a clean silicon surface, and
exposing the clean silicon surface to a microwave plasma formed in a mixed gas of an inert gas primarily formed of Kr, a gas containing nitrogen and a gas containing oxygen to form an oxynitride film on said silicon surface.
17. The method of forming a dielectric film as claimed in claim 16 , wherein said microwave plasma has an electron density of 10 12 cm −3 or less at said silicon surface.
18. The method of forming a dielectric film as claimed in claim 16 , wherein said microwave plasma has a plasma potential of 10V or less at said silicon surface.
19. The method of forming a dielectric film as claimed in claim 16 , wherein said gas containing nitrogen comprises a NH 3 gas, and said gas containing oxygen comprises an O 2 gas.
20. A method of forming a dielectric film comprising exposing a silicon surface to a microwave plasma formed in a mixed gas of an inert gas primarily formed of Kr, a NH 3 gas, and an O 2 gas to form an oxynitride film on said silicon surface, wherein said inert gas and said O 2 gas and said NH 3 gas are supplied with a partial pressure ratio of 96.5:3:0.5.
21. The method of forming a dielectric film as claimed in claim 16 , wherein said silicon surface is exposed to atomic state oxygen (O*) and hydrogen nitride radicals (NH*) in said step of exposing said silicon surface to said microwave plasma.
22. A method of fabricating a semiconductor device, comprising:
removing surface-terminated hydrogens from a silicon substrate by exposing the silicon substrate to a high-density Kr plasma or to low energy Ar ions;
forming a silicon oxide film on the silicon substrate by oxidation;
modifying a surface of said silicon oxide film by exposing the same to hydrogen nitride radicals NH* in the absence of a Si-containing gas; and
forming a gate electrode on said modified silicon oxide film.
23. The method of fabricating a semiconductor device as claimed in claim 22 , wherein said hydrogen nitride radicals (NH*) are formed by microwave plasma formed in a mixed gas of an inert gas selected from the group consisting of Ar and Kr and a gas containing nitrogen and hydrogen.
24. The method of fabricating a semiconductor device as claimed in claim 23 , wherein said microwave plasma has an electron density of 10 12 cm −3 or more at said surface of said silicon substrate.
25. The method of fabricating a semiconductor device as claimed in claim 23 , wherein said microwave plasma has a plasma potential of 10V or less at said surface of said silicon substrate.
26. The method of fabricating a semiconductor device as claimed in claim 23 , wherein said gas containing nitrogen and hydrogen comprises a NH 3 gas.
27. The method of fabricating a semiconductor device as claimed in claim 23 , wherein said silicon oxide film is formed by exposing said silicon surface to a microwave plasma formed in a mixed gas of an inert gas predominantly of Kr and a gas containing oxygen.
28. A method of fabricating a semiconductor device, comprising:
removing surface-terminated hydrogens from a silicon substrate by exposing the silicon substrate to a high-density Kr plasma or to low energy Ar ions;
forming a silicon oxide film on the silicon substrate by oxidation;
modifying a surface of said silicon oxide film by exposing said surface to a microwave plasma formed in a mixed gas of an inert gas selected from the group consisting of Ar and Kr and a gas containing nitrogen and hydrogen in the absence of a Si-containing gas, and
forming a gate electrode on said modified silicon oxide film.
29. The method of fabricating a semiconductor device as claimed in claim 28 , wherein said microwave plasma has an electron density of 10 12 cm −3 or more at said surface of said silicon substrate.
30. The method of fabricating a semiconductor device as claimed in claim 28 , wherein said microwave plasma has a plasma potential of 10V or less at said surface of said silicon substrate.
31. The method of fabricating a semiconductor device as claimed in claim 28 , wherein said gas containing nitrogen and hydrogen comprises a NH 3 gas.
32. The method of fabricating a semiconductor device as claimed in claim 28 , wherein said silicon surface is oxidized by exposing said silicon surface to a microwave plasma formed in a mixed gas of an inert gas of predominantly Kr and a gas containing oxygen.
33. The method of fabricating a semiconductor device as claimed in claim 28 , wherein said silicon oxide film is formed by thermal oxidation.
34. A method of fabricating a semiconductor device, comprising:
exposing a silicon substrate surface to a high-density Kr plasma or to low energy Ar ions in order to remove surface-terminated hydrogens from the silicon substrate surface to form a clean surface,
exposing the clean surface to a microwave plasma formed in a mixed gas of an inert gas primarily formed of Kr, a gas containing nitrogen and a gas containing oxygen in the absence of a Si-containing gas, to form an oxynitride film on said silicon surface; and
forming a gate electrode on said oxynitride film.
35. The method of fabricating a semiconductor device as claimed in claim 34 , wherein said microwave plasma has an electron density of 10 12 cm −3 or more on said silicon substrate.
36. The method of fabricating a semiconductor device as claimed in claim 34 , wherein said microwave plasma has a plasma potential of 10V or less on said silicon substrate.
37. The method of fabricating a semiconductor device as claimed in claim 34 , wherein said gas containing nitrogen comprises a NH 3 gas, and said gas containing oxygen comprises an O 2 gas.
38. A method of fabricating a semiconductor device comprising:
exposing a silicon substrate surface to a microwave plasma formed in a mixed gas of an inert gas primarily formed of Kr, a NH 3 gas, and an O 2 gas to form an oxynitride film on said silicon surface; and
forming a gate electrode on said oxynitride film, wherein said inert gas and said O 2 gas and said NH 3 gas are supplied to a partial pressure ratio of 96.5:3:0.5.
39. The method of fabricating a semiconductor device as claimed in claim 34 , wherein said step of exposing said silicon surface to said microwave plasma comprises exposing said silicon surface to atomic state oxygen (O*) and hydrogen nitride radicals (NH*).
40. A method of forming a dielectric film, comprising:
forming a silicon oxide film on a surface by terminating dangling bonds on a silicon surface with hydrogen, removing the surface-terminating hydrogens, and oxidizing the silicon surface; and
modifying a surface of said silicon oxide film by exposing the same to hydrogen nitride radicals NH*.
41. A method of forming a dielectric film, comprising:
forming a silicon oxide film on a surface by terminating dangling bonds on a silicon surface with hydrogen, removing the surface-terminating hydrogens, and oxidizing the silicon surface; and
modifying a surface of said silicon oxide film by exposing the same to microwave plasma formed in a mixed gas of an inert gas selected from the group consisting of Ar and Kr and a gas containing nitrogen and hydrogen.
42. A method of fabricating a semiconductor device, comprising:
forming a silicon oxide film on a silicon substrate by terminating dangling bonds on a silicon surface with hydrogen, removing the surface-terminating hydrogens, and then oxidizing said surface to form the silicon oxide film;
modifying a surface of said silicon oxide film by exposing the same to hydrogen nitride radicals NH*; and
forming a gate electrode on said modified silicon oxide film.
43. A method of fabricating a semiconductor device, comprising:
forming a silicon oxide film on a silicon substrate by terminating dangling bonds on a silicon surface with hydrogen, removing the surface-terminating hydrogens, and then oxidizing said surface to form the silicon oxide film;
modifying a surface of said silicon oxide film by exposing said surface to a microwave plasma formed in a mixed gas of an inert gas selected from the group consisting of Ar and Kr and a gas containing nitrogen and hydrogen; and forming a gate electrode on said modified silicon oxide film.
44. A method of fabricating a semiconductor device, comprising:
terminating dangling bonds on a silicon surface with hydrogen, removing the surface-terminating hydrogens, and exposing the silicon substrate surface to a microwave plasma formed in a mixed gas of an inert gas primarily formed of Kr, a gas containing nitrogen and a gas containing oxygen, to form an oxynitride film on said silicon surface; and
forming a gate electrode on said oxynitride film.
45. A method of forming a dielectric film comprising:
removing surface-terminated hydrogens from a surface by exposing the surface to a high-density Kr plasma or to low energy Ar ions;
forming a silicon oxide film on the surface; and
modifying said silicon oxide film by exposing a surface of said silicon oxide film to hydrogen nitride radicals (NH*) in the absence of a silicon-containing gas.