TRANSITION-METAL NITRIDE FORMED BY SIMULTANEOUS PHYSISORPTION AND THERMAL EVAPORATION - TIN SI(100)/

It has been confirmed by x-ray photoelectron spectroscopy that the Ti nitride can be athermally formed without substrate disruption by simul taneous NH3 exposure and Ti evaporation to a clean Si(100)-2X1 held at 40 K under ultrahigh vacuum. One of the critical points in the presen t nitride formation at 40 K is solving the kinetic constraint problem by simultaneous adsorption of consisting elements. Compared to TiN for med by other techniques, this athermally formed Ti nitride does not co ntain oxygen contamination but has TiN precursors, TiNxHy. Postheat tr eatment partially converts TiNxHy to Ti nitride and induces the excess ive metallic Ti to be mixed with the previously formed Ti nitride. Whe n the Ti nitride is exposed to the air, Ti in the Ti nitride is prefer entially oxidized and forms the Ti oxide on the top side. By mild-anne aling it up to 550 degrees C under ultrahigh vacuum, the oxygen is tra nsferred from Ti oxide to the Si substrate and the original Ti nitride is gradually recovered. Even for annealing up to the temperature high enough to desorb the oxidized Si, the Ti nitride hardly desorbs. (C) 1998 American Vacuum Society.