Schottky diodes were fabricated using sputter deposited silver contacts to boron doped polycrystalline diamond thin films grown by a hot-filament chemical vapor deposition process with trimethyl borate as an in situ dopant source. High forward current density and a high forward-to-reverse current ratio were exhibited by these diodes. Current density-voltage and capacitance-voltage-frequency characteristics of these diodes are very similar to those of Schottky diodes fabricated using a single-crystal diamond substrate.