The Schottky contact of Co, its silicide and germanosilicide on n-poly-Si0.84Ge0.16 layer, was investigated. Amorphous Si0.84Ge0.16 layer was deposited on n-Si (100) substrate by ion beam sputtering (IBS). The layer was doped through thermal diffusion of phosphorus to fabricate n-poly-Si0.84Ge0.16 thin film. The Schottky diodes were formed by deposition of Co on n-poly-Si0.84Ge0.16 by the IBS technique. Solid-phase reaction between Co and n-poly-Si0.84Ge0.16 by rapid thermal annealing (RTA) as a function of temperature was studied. Phase identification and atomic depth profile were characterized by x-ray diffraction and Auger electron spectroscopy, respectively. The current-voltage and capacitance-voltage characteristics of both as-deposited and annealed Co/n-poly-Si0.84Ge0.16 Schottky diodes were investigated. The results reveal that the Schottky barrier height (SBH) keeps nearly constant with the annealing temperature between 300 and 600℃. The constancy of the SBH confirms the fact that Co and its silicides contacting with the same semiconductor have the close Schottky barrier height.