NUCLEATION AND INITIAL GROWTH OF BIAS-ASSISTED HFCVD DIAMOND ON BORON-NITRIDE FILMS

Diamond was grown on boron nitride thin films deposited on silicon sub strates. The effects of substrate biasing on the nucleation and growth of diamond were studied. Boron nitride (BN) films were obtained by rf plasma CVD. FT-IR analysis of the BN films revealed a hexagonal struc ture and a high transparency. The diamond deposition process was carri ed out in a bias-assisted hot filament reactor. Both positive and nega tive biases relative to the filament were applied to BN-coated Si subs trates. The density and morphology of the diamond crystallites in the early stages of the nucleation were studied by scanning electron micro scopy. We found that negative substrate biases higher than 200 V great ly increased the nucleation density of diamond, reaching a maximum of 10(10) cm(-2) for - 250 V. After the nucleation stage, continuous diam ond films were grown under standard deposition conditions and Raman an alysis revealed the high quality of the diamond films. (C) 1997 Elsevi er Science S.A.