Tungsten gate method and apparatus

A method of fabricating a gate electrode stack on a substrate, comprising:

• forming an insulating film on the substrate;
• forming a conductor film on the insulating film by initially depositing a film of a combination of amorphous silicon and amorphous tungsten, and thereafter depositing a film of polycrystalline tungsten on the film of a combination of amorphous silicon and amorphous tungsten and annealing the substrate to react the amorphous silicon with the amorphous tungsten to form tungsten silicide on the insulating film and to increase the grain structure of the polycrystalline tungsten film;
• and
• patterning the tungsten silicide film and the polycrystalline tungsten film to define the gate electrode stack.

A circuit device, comprising:

• a substrate;
• an insulating film on the substrate;
• a tungsten silicide film on the insulating film and having a sufficient amount of unbonded silicon to bond the tungsten silicide film to the insulating film;
• and
• a polycrystalline tungsten film on the tungsten silicide film.

A method of fabricating a circuit device, comprising:

• forming an insulating film on a substrate;
• forming a film of amorphous silicon and amorphous tungsten on the insulating film by exposing the insulating film to an ambient of WF6 and SiH4;
• forming a film of polycrystalline tungsten on the film of amorphous silicon and amorphous tungsten;
• and
• annealing the substrate to react the amorphous silicon with the amorphous tungsten to form tungsten silicide on the insulating film and to increase the grain structure of the polycrystalline tungsten film.