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The spatial distributions of the Schottky barrier heights of ultrathin CoSi 2 films (~ 10 nm) on n-Si (100), obtained by multilayer solid state reaction of Co/Ti/n-Si, Co/a-Si/Ti/n-Si, Ti/Co/a-Si/Ti/n-Si and Co/n-Si systems, are studied by ballistic electron emission microscopy (BEEM) and spectroscopy (BEES) at low temperature (~-80 C). The barrier heights determined from BEEM spectra range between 520 meV and 700 meV, with an approximate Gaussian distribution. The mean barrier heights of the epitaxial CoSi 2/Si contacts are 0.60-0.61 eV, lower than the 0.64 eV for polycrystalline CoSi 2/Si contacts. Adding a thin amorphous Si interlayer (1 nm) slightly increases the probability of higher barrier heights, while a thin Ti capping layer (1 nm) has no significant influence on the mean barrier height. The BEEM results are compared to those from I-V/C-Vmeasurements.