Nickel Silicides Grown on Amorphous Silicon and Silicon-Germanium Thin Films

Abstract

Nickel silicides are grown on amorphous silicon and silicon-germanium films at temperatures ≤ 300°C. Nickel silicides with sheet resistance of 11 and 15 Ω/ٗ were fabricated on amorphous silicon films at temperatures of 300 and 250°C, respectively. These resistances are comparable to silicides formed on single-crystal silicon. Such low resistances could also be obtained in samples where nickel was annealed with amorphous silicon-germanium at 300°C for 30 min; however, the resistances of the same films were considerably higher when the annealing temperature was 250°C. X-ray photoelectron spectroscopy seems to suggest that the high resistance in silicon-germanium samples which were annealed at 250°C was caused by formation of a Ni-Si-Ge cluster through physical mixing of atoms. However, at a temperature of 300°C, silicon and germanium reacted with nickel in separate layers.