DIAMOND DEPOSITION ON POLYCRYSTALLINE FILMS OF CUBIC BORON-NITRIDE

We have grown diamond films on films of cubic boron nitride (cBN). The cBN films were grown on Si(100) substrates using ion-assisted pulsed laser deposition. Fourier transform infrared (FTIR) spectroscopy indicated that the BN films contained approximately 75% sp3-bonded cBN. The as-grown cBN films were inserted with no surface pretreatment (e.g., abrading or scratching) into a conventional hot filament diamond reactor. In situ Raman spectroscopy was used to confirm diamond synthesis during growth. The nucleation density of the diamond films was estimated at 1 X 10(9)/CM2, equivalent to or higher than the best values for scratched silicon substrates. In addition, we found that the cBN films were etched in the diamond reactor; a film thickness greater than or similar to 1500 angstrom was required to prevent total film loss before diamond nucleation occurred. The presence of cBN under the diamond was established using FTIR spectroscopy 'and Auger electron spectroscopy.