A gate dielectric and method of fabricating a gate dielectric that
produces a more reliable and thinner equivalent oxide thickness than
conventional SiO.sub.2 gate oxides are provided. Gate dielectrics formed
from metals such as zirconium are thermodynamically stable such that the
gate dielectrics formed will have minimal reactions with a silicon
substrate or other structures during any later high temperature
processing stages. The addition of nitrogen to the microstructure of the
gate dielectric promotes an amorphous phase that further improves the
electrical properties of the gate dielectric. The process shown is
performed at lower temperatures than the prior art, which inhibits
unwanted species migration and unwanted reactions with the silicon
substrate or other structures. By using a thermal evaporation technique
to first deposit a metal layer, the underlying substrate surface
smoothness is preserved, thus providing improved and more consistent
electrical properties in the resulting gate dielectric.