Dielectric film and formation method thereof, semiconductor device, non-volatile semiconductor memory device, and fabrication method for a semiconductor device

• US 20080277715A1
• Filed: 10/31/2007
• Published: 11/13/2008
• Est. Priority Date: 12/28/2000
• Status: Active Grant

• Current Assignee: Masaki Hirayama, Shigetoshi Sugawa, Tadahiro Ohmi, Yasuyuki Shirai
• Original Assignee: Masaki Hirayama, Shigetoshi Sugawa, Tadahiro Ohmi, Yasuyuki Shirai
• Inventors: Ohmi, Tadahiro, Hirayama, Masaki, Sugawa, Shigetoshi, Shirai, Yasuyuki
• Granted Patent: US 7,718,484 B2
• Time in Patent Office: Days
• US Class Current: 257/321
• CPC Class Codes: H01L 21/0214 the material being a silicon oxynitride, e.g. SiON or SiON:H
• CPC Class Codes: H01L 21/02164 the material being a silicon oxide, e.g. SiO2
• CPC Class Codes: H01L 21/0217 the material being a silicon nitride not containing oxygen, e.g. SixNy or SixByNz H01L21/02126 and H01L21/0214 take precedence
• CPC Class Codes: H01L 21/02238 silicon in uncombined form, i.e. pure silicon
• CPC Class Codes: H01L 21/02247 formation by nitridation, e.g. nitridation of the substrate
• CPC Class Codes: H01L 21/02249 formation by combined oxidation and nitridation performed simultaneously
• CPC Class Codes: H01L 21/02252 formation by plasma treatment, e.g. plasma oxidation of the substrate after treatment of an insulating film by plasma H01L21/3105 and subgroups
• CPC Class Codes: H01L 21/02315 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/02332 into an oxide layer, e.g. changing SiO to SiON
• CPC Class Codes: H01L 21/0234 treatment by exposure to a plasma
• CPC Class Codes: H01L 21/28202 in a nitrogen-containing ambient, e.g. nitride deposition, growth, oxynitridation, NH3 nitridation, N2O oxidation, thermal nitridation, RTN, plasma nitridation, RPN
• CPC Class Codes: H01L 21/28211 in a gaseous ambient using an oxygen or a water vapour, e.g. RTO, possibly through a layer H01L21/28194 and H01L21/28202 take precedence
• CPC Class Codes: H01L 21/2822 with substrate doping, e.g. N, Ge, C implantation, before formation of the insulator
• CPC Class Codes: H01L 21/30604 Chemical etching
• CPC Class Codes: H01L 21/3144 on silicon
• CPC Class Codes: H01L 21/31662 of silicon in uncombined form
• CPC Class Codes: H01L 21/3185 of siliconnitrides
• CPC Class Codes: H01L 21/823462 with a particular manufacturing method of the gate insulating layers, e.g. different gate insulating layer thicknesses, particular gate insulator materials or particular gate insulator implants
• CPC Class Codes: H01L 27/105 including field-effect components
• CPC Class Codes: H01L 27/12 the substrate being other than a semiconductor body, e.g. an insulating body
• CPC Class Codes: H01L 29/4908 : for thin film semiconductor, e.g. gate of TFT
• CPC Class Codes: H01L 29/513 : the variation being perpendicular to the channel plane
• CPC Class Codes: H01L 29/517 : the insulating material comprising a metallic compound, e.g. metal oxide, metal silicate H01L29/518 takes precedence
• CPC Class Codes: H01L 29/518 : the insulating material containing nitrogen, e.g. nitride, oxynitride, nitrogen-doped material
• CPC Class Codes: H01L 29/66757 : Lateral single gate single channel transistors with non-inverted structure, i.e. the channel layer is formed before the gate
• CPC Class Codes: H01L 29/78603 : characterised by the insulating substrate or support H01L29/78657 takes precedence
• CPC Class Codes: H01L 29/78645 : with multiple gate
• CPC Class Codes: H10B 41/40 : characterised by the peripheral circuit region
• CPC Class Codes: H10B 41/49 : comprising different types of peripheral transistor
• CPC Class Codes: H10B 43/30 : characterised by the memory core region
• CPC Class Codes: H10B 99/00 : Subject matter not provided for in other groups of this subclass

Abstract

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.

Claims

1. A dielectric film formed on a silicon surface that is free of surface-terminating hydrogen, said dielectric film containing therein a rare gas element and further nitrogen with a concentration distribution such that a nitrogen concentration increase toward the surface of said dielectric film from a central part of said dielectric film,

wherein said insulation dielectric film contains hydrogen atoms of not more than 10¹²/cm².

2. The dielectric film as claimed in claim 1, wherein said nitrogen concentration increases in said dielectric film also in the vicinity of an interface with said silicon surface as compared with a central part of said dielectric film.

3. The dielectric film as claimed in claim 1, wherein said dielectric film comprises a silicon oxynitride film, and wherein said nitrogen concentration becomes minimum at a central part of said film.

4. The dielectric film as claimed in claim 1, wherein said dielectric film is essentially a silicon nitride film at a film surface contacting with an electrode provided on the surface of said dielectric film.

5. The dielectric film as claimed in claim 1, wherein said dielectric film is essentially silicon oxide at a central part of said film.

7. The semiconductor device as claimed in claim 5, wherein said nitrogen concentration increases in said insulation film in the vicinity to an interface to said silicon substrate as compared with said central part.

6. A semiconductor device, comprising:

a silicon substrate having a surface that is essentially free of surface-terminating hydrogen;

an insulation film formed on said silicon substrate surface; and

an electrode formed on said insulation film,

wherein said insulation film contains therein a rare gas element and nitrogen, the concentration of said nitrogen increases toward the film surface of said insulation film contacting with said electrode from a central part of said film.

8. The semiconductor device as claimed in claim 6, wherein said insulation film is a silicon oxynitride film, and wherein said nitrogen concentration becomes minimum at said central part of said film.

9. The semiconductor device as claimed in claim 6, wherein said insulation film substantially has a composition of silicon nitride at a film surface contacting with said electrode.

10. The semiconductor device as claimed in claim 6, wherein said insulation film substantially has a composition of silicon oxide at said central part of said film.

11. The semiconductor device as claimed in claim 6, wherein there is further provided a second electrode on said first electrode via an inter-electrode insulation film.

12. A non-volatile semiconductor memory device, comprising:

a silicon substrate having a surface that is essentially free of surface-terminating hydrogen;

a tunneling insulation film formed on said silicon substrate surface;

a floating gate electrode formed on said tunneling insulation film;

an inter-electrode insulation film formed on said floating gate electrode; and

a control gate electrode formed on said inter-electrode insulation film,

at least one of said tunneling insulation film and said inter-electrode insulation film containing therein a rare gas element and nitrogen, and the concentration of said nitrogen increasing toward a film surface from a central part of said film.

13. The non-volatile semiconductor device as claimed in claim 12, wherein said nitrogen concentration increases also in said tunneling insulation film near an interface to said silicon substrate as compared with said central part of said film.

14. The non-volatile semiconductor device as claimed in claim 12, wherein said tunneling insulation film comprises a silicon oxynitride film and wherein said nitrogen concentration becomes minimum at a central part of said film.

15. The non-volatile semiconductor device as claimed in claim 12, wherein said tunneling insulation film substantially has a composition of silicon nitride at a film surface contacting with said electrode.

16. The non-volatile semi semiconductor device as claimed in claim 12, wherein said tunneling insulation film substantially has a composition of silicon oxide at a central part of said film.

17. A method of forming a dielectric film, comprising:

forming a silicon oxide film on a 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, 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 mixed gas of N₂ gas and H₂ gas.

18. A method of forming a dielectric film, comprising:

forming a silicon oxide film on a 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 mixed gas of N₂ gas and H₂ gas in the absence of a Si-containing gas.

19. A method of fabricating a semiconductor device, comprising:

forming a silicon oxide film on a 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, 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 mixed gas containing N₂ gas and H₂ gas.

20. A method of fabricating a semiconductor device, comprising:

forming a silicon oxide film on a 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 mixed gas of N₂ gas and H₂ gas in the absence of a Si-containing gas, and

forming a gate electrode on said modified silicon oxide film.

21. A semiconductor device, comprising:

a semiconductor substrate; and

an insulation film formed thereon,

wherein an interface between said semiconductor substrate and said insulation film is free from hydrogen terminating a surface of said semiconductor substrate

wherein said insulation film contains hydrogen atoms of not more than 10¹²/cm².

22. The semiconductor device as claimed in claim 21, wherein said insulation film comprises any of silicon oxide, silicon nitride and silicon oxynitride.

23. The method as claimed in claim 21, wherein said insulation film contains nitrogen with a concentration higher at surface part thereof as compared with a central part thereof.

24. A method of fabricating a semiconductor device, comprising the steps of:

removing hydrogen atoms terminating a surface of a semiconductor substrate by exposing said surface of said semiconductor substrate to rare gas plasma; and

forming a film on said semiconductor substrate surface from which said terminating hydrogen atoms are removed.

25. The method as claimed in claim 24, wherein said film comprises any of silicon oxide, silicon nitride and silicon oxynitride.