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 semiconductor structure comprising: 
 a semiconductor substrate;    an interfacial layer located on said semiconductor substrate;    a high k dielectric located on said interfacial layer; and    a HfSiN gate metal located on said high k dielectric.    
   
   
       2 . The semiconductor structure of  claim 1  wherein said semiconductor substrate comprises one of Si, Ge, SiGe, SiC, SiGeC, Ga, GaAs, InAs, InP, other II/IV or III/VI compound semiconductors, organic semiconductors or layered semiconductors.  
   
   
       3 . The semiconductor structure of  claim 2  wherein said semiconductor substrate is a Si-containing semiconductor material.  
   
   
       4 . The semiconductor structure of  claim 1  wherein said interfacial layer comprises atoms of Si and O, and optionally N.  
   
   
       5 . The semiconductor structure of  claim 4  wherein said interfacial layer comprises SiO 2 , SiON or silicates thereof.  
   
   
       6 . The semiconductor structure of  claim 1  wherein said interfacial layer has a dielectric constant from about 4.0 to about 20 and a thickness from about 0.1 to about 5 nm.  
   
   
       7 . The semiconductor structure of  claim 1  wherein said interfacial layer has a Si content from about 1 to about 80 atomic percent.  
   
   
       8 . The semiconductor structure of  claim 1  wherein said interfacial layer has a Si content that is graded.  
   
   
       9 . The semiconductor structure of  claim 1  wherein said high k dielectric has a dielectric constant that is greater than 4.0 and a thickness from about 0.5 to about 10 nm.  
   
   
       10 . The semiconductor structure of  claim 1  wherein said high k dielectric comprises an oxide, nitride, oxynitride, silicate or mixtures thereof.  
   
   
       11 . The semiconductor structure of  claim 1  wherein said high k dielectric is a Hf based material.  
   
   
       12 . The semiconductor structure of  claim 1  wherein said interfacial layer comprises SiO 2  or SiON and said high k dielectric comprises HfO 2 , Hf silicate or Hf oxynitride.  
   
   
       13 . The semiconductor structure of  claim 1  wherein said HfSiN has a workfunction between 4.0 and 4.5 eV.  
   
   
       14 . The semiconductor structure of  claim 1  further comprising a Si-containing conductive material atop said HfSiN layer.  
   
   
       15 . The semiconductor structure of  claim 1  wherein said interfacial layer, said high k dielectric and said HfSiN gate metal are patterned into a gate region.  
   
   
       16 . 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.    
   
   
       17 . The method of  claim 16  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.  
   
   
       18 . The method of  claim 17  wherein n is 0 and said Si source is SiH 4 .  
   
   
       19 . The method of  claim 16  wherein said Si source is a solid, liquid or gas.  
   
   
       20 . The method of  claim 16  wherein Si source is diluted with from about 70 to about 99% He.  
   
   
       21 . The method of  claim 16  wherein the Ar/N 2 /Si source has a flow ratio of from about 1-100/1-100/1-100 sccm, respectively  
   
   
       22 . 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.    
   
   
       23 . The method of  claim 22  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  
   
   
       24 . The method of  claim 23  wherein n is 0 and said Si source is SiH 4 .  
   
   
       25 . The method of  claim 22  wherein said Si source is a solid, liquid or gas.  
   
   
       26 . The method of  claim 22  wherein Si source is diluted with from about 70 to about 99% He.  
   
   
       27 . The method of  claim 22  wherein the Ar/N 2 /Si source has a flow ratio of from about 1-100/1-100/1-100 sccm, respectively  
   
   
       28 . The method of  claim 22  further comprising forming a Si-containing conductive material atop said HfSiN film.  
   
   
       29 . The method of  claim 22  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.  
   
   
       30 . The method of  claim 28  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.