Transition metal alloys for use a gate electrode and device incorporating these alloys

Abstract

Embodiments of a transition metal alloy having an n-type or p-type work function that does not significantly shift at elevated temperature. The disclosed transition metal alloys may be used as, or form a part of, the gate electrode in a transistor. Methods of forming a gate electrode using these transition metal alloys are also disclosed.

1 . An alloy comprising: 
 approximately 20 to 50 atomic percent of a transition metal, the transition metal selected from a group consisting of titanium, zirconium, tantalum, and hafnium;    approximately 30 to 60 atomic percent of carbon; and    up to approximately 20 atomic percent of aluminum.    
   
   
       2 . The alloy of  claim 1 , wherein the alloy has a work function in a range of approximately 3.8 eV to 4.4 eV.  
   
   
       3 . The alloy of  claim 2 , wherein the work function does not significantly shift at a temperature up to approximately 900° Celsius.  
   
   
       4 . The alloy of  claim 1 , further comprising up to 5 atomic percent of a residual material, the residual material comprising at least one of oxygen, nitrogen, and chloride.  
   
   
       5 . An alloy comprising: 
 approximately 20 to 50 atomic percent of a transition metal;    approximately 30 to 60 atomic percent of a combination of one or more elements, the combination of elements including at least one element selected from a group consisting of carbon, nitrogen, silicon, germanium, and boron; and    up to approximately 20 atomic percent of a dopant.    
   
   
       6 . The alloy of  claim 5 , wherein the alloy has a work function of between approximately 3.8 eV to 4.4 eV.  
   
   
       7 . The alloy of  claim 5 , wherein the alloy has a work function of between 4.9 eV and 5.5 eV.  
   
   
       8 . The alloy of  claim 5 , wherein the alloy has a work function that does not significantly shift at a temperature up to approximately 900° Celsius.  
   
   
       9 . The alloy of  claim 5 , wherein the transition metal is selected from a group consisting of titanium, zirconium, tantalum, hafnium, tungsten, chromium, molybdenum, vanadium, and niobium.  
   
   
       10 . The alloy of  claim 5 , further comprising up to 5 atomic percent of a residual material, the residual material comprising at least one of oxygen, nitrogen, and chloride.  
   
   
       11 . The alloy of  claim 5 , wherein the dopant is selected from a group consisting of aluminum, platinum, silicon, gallium, and germanium.  
   
   
       12 . An alloy comprising: 
 approximately 37 atomic percent of titanium;    approximately 55 atomic percent of carbon; and    approximately 3 atomic percent of aluminum;    wherein the alloy has a work function of between approximately 3.8 eV and 4.4 eV.    
   
   
       13 . The alloy of  claim 12 , wherein the work function does not significantly shift at a temperature up to approximately 900° Celsius.  
   
   
       14 . The alloy of  claim 12 , further comprising approximately 4 atomic percent of oxygen and less than 1 atomic percent of nitrogen.  
   
   
       15 - 45 . (canceled)