Avgerinos V. Gelatos

The effects of reactive precleaning (RPC+) on the formation of titanium silicide by PECVD TiCl/sub 4/-Ti deposition, and its thermal stability

We have performed the defect characterization of Reactive Precleaning (RPC+), an in-Situ precleaning prior to PECVD TiCl/sub 4/-Ti deposition, compared its cleaning efficiency with HF wet cleaning, and evaluated thermal stability of the silicide. RPC+ was found to be a defect free cleaning process, and TiCl/sub 4/-Ti deposition with in-Situ RPC+ results in thicker silicide on the undoped, n/sup +/, and p/sup +/-Si substrate due to the interface cleanliness. It was observed by TEM and XRD that the Ti-silicide with RPC+ has highly textured C49 phase. Finally, RPC+ improves the thermal stability of the silicide.

Effect of NH3 thermal treatment on an atomic layer deposited on tungsten films and formation of W–B–N

The effect of ammonia (NH3) ambient annealing on a tungsten (W) film deposited by atomic layer deposition at temperatures ranging from 400–700 °C is discussed. The as-deposited film contains approximately 20 at. % of boron which is chemical bound to W (W–B) having a resistivity of 128 μΩ cm. The film has an amorphous structure, which does not transform into crystalline phase during annealing. As a result of annealing in NH3 ambient, a tungsten ternary phase (W–B–N) forms at the surface; its binding configuration depends on the annealing temperature. Below 500 °C, nitrogen is chemically bonded to tungsten (W–N) while maintaining a W–B bond. Above 600 °C, nitrogen-rich W–B–N forms, in which nitrogen atoms have chemical binding with boron (B–N) and tungsten (W–N). It was found that a film annealed at higher temperatures has a resistivity of 107 μΩ cm, and thermal desorption of boron and nitrogen containing species is not observed during the thermal process. In addition, tungsten oxide formed at the surface d...