METHOD OF FORMING HfSiN METAL FOR n-FET APPLICATIONS

Abstract

A compound metal comprising HfSiN which is a n-type metal having a workfunction of about 4.0 to about 4.5, preferably about 4.3, eV which is thermally stable on a gate stack comprising a high k dielectric and an interfacial layer. Furthermore, after annealing the stack of HfSiN/high k dielectric/ interfacial layer at a high temperature (on the order of about 1000° C.), there is a reduction of the interfacial layer, thus the gate stack produces a very small equivalent oxide thickness (12 Å classical), which cannot be achieved using TaSiN.

1 . A method of fabricating a HfSiN metal compound comprising:
 providing a Hf target and an atmosphere that comprises Ar/N 2 /a Si source diluted with He; and sputtering a HfSiN film from said Hf target in said atmosphere.   
     
     
         2 . The method of  claim 1  wherein said Si source has the formula SiH 4-n R n  wherein n is 0, 1, 2, 3 or 4 and R is an aliphatic moiety containing from 1 to about 18 carbon atoms. 
     
     
         3 . The method of  claim 2  wherein n is 0 and said Si source is SiH 4 . 
     
     
         4 . The method of  claim 1  wherein said Si source is a solid, liquid or gas. 
     
     
         5 . The method of  claim 1  wherein Si source is diluted with from about 70 to about 99% He. 
     
     
         6 . The method of claim I wherein the Ar/N 2 /Si source has a flow ratio of from about 1-100/1-100/1-100 sccm, respectively. 
     
     
         7 . A method of forming a semiconductor structure comprising:
 providing a stack comprising a high k dielectric and an interfacial layer on a surface of a substrate; forming a HfSiN film on said stack, wherein said HfSiN film is formed by providing a Hf target and an atmosphere that comprises Ar/N 2 /a Si source diluted with He and sputtering a HfSiN film from said Hf target in said atmosphere.   
     
     
         8 . The method of  claim 7  wherein said Si source has the formula SiH 4-n R n  wherein n is 0, 1, 2, 3 or 4 and R is an aliphatic moiety containing from 1 to about 18 carbon atoms. 
     
     
         9 . The method of  claim 8  wherein n is 0 and said Si source is SiH 4 . 
     
     
         10 . The method of  claim 7  wherein said Si source is a solid, liquid or gas. 
     
     
         11 . The method of  claim 7  wherein Si source is diluted with from about 70 to about 99% He. 
     
     
         12 . The method of  claim 7  wherein the Ar/N 2 /Si source has a flow ratio of from about 1-100/1-100/1-100 sccm, respectively. 
     
     
         13 . The method of  claim 7  further comprising forming a Si-containing conductive material atop said HfSiN film. 
     
     
         14 . The method of  claim 7  further comprising the step of patterning said HfSiN film and said stack comprising said high k dielectric and said interfacial layer into a patterned gate region. 
     
     
         15 . The method of  claim 13  further comprising the step of patterning said Si-containing conductive material, said HfSiN film and said stack comprising said high k dielectric and said interfacial layer into a patterned gate region.