a process for passivating the semiconductor - dielectric interface of a mos structure to reduce the interface state density to a very low level . a particular example is a mosfet having a tungsten electrode that in the past has prevented passivation of the underlying semiconductor - dielectric interface to an extent sufficient to reduce the interface state density to less than 5 × 10 10 / cm 2 - ev . though substantially impervious to molecular hydrogen , thin tungsten layers are shown to be pervious to atomic hydrogen , enabling atomic hydrogen to be diffused through a tungsten electrode into an underlying semiconductor - dielectric interface . three general approaches are encompassed : forming an aluminum - tungsten electrode stack in the presence of hydrogen so as to store atomic hydrogen between the tungsten and aluminum layers , followed by an anneal to cause the atomic hydrogen to diffuse through the tungsten layer and into the interface ; subjecting a tungsten electrode to hydrogen plasma , during which atomic hydrogen diffuses through the electrode and into the semiconductor - dielectric interface ; and implanting atomic hydrogen into tungsten electrode , followed by an anneal to cause the atomic hydrogen to diffuse through the electrode and into the semiconductor - dielectric interface .