A novel metal gate structure includes a gate oxide layer formed on a surface
of
a silicon substrate, a doped silicon layer stacked on the gate oxide layer, a CVD
ultra-thin titanium nitride film deposited on the doped silicon layer, a tungsten
nitride layer stacked on the CVD ultra-thin titanium nitride film, a tungsten layer
stacked on the tungsten nitride layer, and a nitride cap layer stacked on the tungsten
layer. A liquid phase deposition (LPD) oxide spacer is formed on each sidewall
of the metal gate stack. A silicon nitride spacer is formed on the LPD oxide spacer.
The thickness of the CVD ultra-thin titanium nitride film is between 10 and 100 angstroms.