Forming Method and Forming System for Insulation Film

Abstract

A gate insulation film ( 104 ) of a MISFET ( 100 ) is constituted of a silicon oxide film ( 106 ), silicon nitride film ( 107 ), and high-permittivity film ( 108 ). The silicon oxide film ( 106 ) and silicon nitride film ( 107 ) are formed by microwave plasma processing with a radial line slot antenna.

1 . A method for forming a gate insulating film, comprising the steps of:
 removing a natural oxide film formed on a silicon substrate;   generating plasma of process gas on said silicon substrate, and forming a silicon oxynitride film by reforming a surface of said silicon substrate using said plasma; and   forming a high-permittivity film on said silicon oxynitride film, wherein   said step of forming said silicon oxynitride film includes:   exposing the surface of said silicon substrate to plasma generated by irradiating process gas containing oxygen with high frequency energy via an antenna, and oxidizing the surface of said silicon substrate by said plasma, and   exposing a surface of said silicon oxide film to plasma generated by irradiating process gas containing nitrogen with high frequency energy via an antenna, and nitriding the surface of said silicon substrate by said plasma.   
     
     
         2 . The method according to  claim 1 , wherein:
 said step of removing natural oxide film includes generating activated species of N and H by plasma of a mixed gas of N 2  gas and H 2  gas, adding NF 3 , gas to the activated species to generate activated species of N, H and NF 3 , reacting the activated species with the natural oxide film on said silicon substrate, and generating a by-product of reaction, and thereby removes the natural oxide film.   
     
     
         3 . The method according to  claim 1 , wherein said high-permittivity film contains at least one of Al 2 O 3 , HfSiO 2 , Ta 2 O 5 , ZrSiO 2 , HfO 2 , and ZrO 2 . 
     
     
         4 . The method according to  claim 1 , further comprising a step of annealing said high-permittivity film includes exposing the surface of said high-permittivity film to plasma of a gas including oxygen. 
     
     
         5 . The method according to  claim 1 , wherein said gas containing oxygen includes Ar and H 2 . 
     
     
         6 . A method for forming a gat insulating film comprising the steps of:
 preparing a silicon substrate on a surface of which an oxide film is formed;   generating plasma of a gas containing oxygen on said silicon substrate, reforming said oxide film by said plasma and forming a silicon oxide film;   generating plasma of a gas containing nitrogen on said silicon substrate, nitriding the surface of said silicon oxide film by said plasma;   forming a high-permittivity film on the nitrided silicon oxide film by CVD.   
     
     
         7 . The method according to  claim 6 , wherein said high-permittivity film contains at least one of Al 2 O 3 , HfSiO 2 , Ta 2 O 5 , ZrSiO 2 , HfO 2 , and ZrO 2 . 
     
     
         8 . The method according to  claim 6 , further comprising a step of annealing said high-permittivity film includes exposing the surface of said high-permittivity film to plasma of a gas including oxygen. 
     
     
         9 . The method according to  claim 6 , wherein said gas containing oxygen includes Ar and H 2 . 
     
     
         10 . A method for forming a gate insulating film, comprising
 generating plasma of a gas containing nitrogen gas on a surface of a silicon substrate, nitriding the surface of said silicon substrate by said plasma and forming a silicon nitride film,   forming a high-permittivity film on said silicon nitride film, and   annealing said high-permittivity film.   
     
     
         11 . The method according to  claim 10 , wherein said plasma is generated by applying microwaves via a plane antenna having a plurality of slits. 
     
     
         12 . The method according to  claim 10 , further comprising a step of removing a natural oxide film on said silicon substrate. 
     
     
         13 . The method according to  claim 12 , wherein
 said step of removing natural oxide film includes generating activated species of nitrogen and hydrogen by plasma of a mixed gas of N 2  gas and H 2  gas, adding NF 3  gas to the activated species to generate activated species of nitrogen, hydrogen and NF 3 , reacting the activated species with the natural oxide film on said silicon substrate, and generating a by-product of reaction, and thereby removes the natural oxide film.   
     
     
         14 . The method according to  claim 10 , wherein
 said step of forming the silicon nitride film is performed to is directly reformed from a natural oxide film which has already been formed on said silicon substrate.   
     
     
         15 . The method according to  claim 10 , wherein said high-permittivity film contains at least one of Al 2 O 3 , HfSiO 2 , Ta 2 O 5 , ZrSiO 2 , HfO 2 , and ZrO 2 . 
     
     
         16 . The method according to  claim 10 , wherein said step of annealing said silicon substrate includes exposing the surface of said silicon substrate to plasma of a gas including oxygen. 
     
     
         17 . The method according to  claim 10 , wherein said gas containing oxygen includes Ar and H 2 . 
     
     
         18 . A method for forming a gate insulating film comprising the steps of:
 exposing an oxide film that has already been formed on a silicon substrate to plasma of a gas containing oxygen and reforming said already-formed oxide film to a silicon oxide film;   generating plasma of a gas containing nitrogen on said silicon substrate, nitriding the surface of said silicon oxide film by said plasma;   forming a high-permittivity film on the nitrided silicon oxide film by CVD.   
     
     
         19 . The method according to  claim 18 , wherein said high-permittivity film contains at least one of Al 2 O 3 , HfSiO 2 , Ta 2 O 5 , ZrSiO 2 , HfO 2 , and ZrO 2 . 
     
     
         20 . The method according to  claim 18 , further comprising a step of annealing said high-permittivity film includes exposing the surface of said high-permittivity film to plasma of a gas including oxygen. 
     
     
         21 . The method according to  claim 18 , wherein said gas containing oxygen includes Ar and H 2 .