GROWTH OF DIAMOND FILMS ON SIC, WC AND CUBIC BN SUBSTRATES

The growth morphology of diamond films grown on single crystals of SIC and on sintered WC and cubic BN (CBN) substrates by hot filament assi sted chemical vapour deposition was examined using transmission electr on microscopy and scanning electron microscopy. Diamond was found to h ave the form of particles on the substrates of SiC and WC in the initi al stage of film growth. Both an amorphous layer and a directly bonded a rea were seen at the interface. Several orientation relationships, different from the cube/cube relation, were observed in these systems. On the other hand, in the case of diamond films on CBN substrates, th e growth morphology of diamond was affected by the surface condition o f the substrates. When CBN substrates were polished with a diamond pas te before deposition, diamond grew in the form of particles. The growt h morphology was changed by ion sputtering of the surface of the subst rate from particle growth to uniform film growth. These results are di scussed on the basis of lattice mismatch at the interface.