Aluminum and nickel contact metallizations have been investigated on polycrystalline, randomly oriented diamond films of varying dopant concentrations. Hall measurements have been used to characterize the diamond films to indicate good control of dopant incorporation with carrier mobility comparable with those of the highest reported in similar films. Rectifying characteristics have been observed for both Al and Ni contacts provided the sheet resistance of the films is greater than 1200 &OHgr;/sq. The thermal stability of these contacts have been investigated to 400 °C and Al diodes have been found to be electrically stable to such treatments. ©1995 American Institute of Physics.