The infrared response of polycrystalline and epitaxial CoSi2/Si Schottky diodes with similar silicide thickness has been measured. For the polycrystalline diodes the quantum efficiency is found to be two times higher than for the epitaxial diodes, although both types of diodes present very similar barrier height. The observed improvement is attributed to grain boundary scattering of the excited carriers. ©1995 American Institute of Physics.