Nickel silicides grown on amorphous silicon and silicon-germanium thin films

Nickel silicides are grown on amorphous silicon and silicon-germanium films at temperatures less than or equal to 300 degrees C. Nickel silicides with sheet resistance of 11 and 15 Omega/square were fabricated on amorphous silicon films at temperatures of 300 and 250 degrees 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 degrees C for 30 min; however, the resistances of the same films were considerably higher when the annealing temperature was 250 degrees C. X-ray photoelectron spectroscopy seems to suggest that the high resistance in silicon- germanium samples which were annealed at 250 degrees C was caused by formation of a Ni-Si-Ge cluster through physical mixing of atoms. However, at a temperature of 300 degrees C, silicon and germanium reacted with nickel in separate layers. (C) 1998 The Electrochemical Society. S1099-0062(98)04-105-4. All rights reserved.