Role of embedded titanium nanoparticles for enhanced chemical vapor deposition diamond formation on silicon

The influence of titanium nanoparticles embedded in the surface of silicon substrates by ultrasonic agitation on diamond chemical vapor deposition was studied. The deposited diamond particle density (DPD) was found to be subs tantially enhanced by using a mixed slurry (Di/Ti) compared to abrasion wit h a diamond slurry solely. It was also determined that, under the ultrasoni c agitation conditions used in this work, the addition of titanium particle s to the abrasive suspension does not affect the quantity of embedded diamo nd growth centers, nor does it alter their chemical character, Rather, the Ti particle additives are active during the initial stages of deposition. I on implication experiments show that diamond homoepitaxially,grows on diamo nd residues, and that Ti residues do not serve as nucleation centers. The a nnihilation of diamond growth centers prior to stable substrate formation i s attributed to hydrogen etching, while the effect of thermal annealing is negligible. These experiments show that Ti residues do not prevent the etch ing of diamond debris, We therefore conclude that the increase in DPD is re lated to an enhancement in diamond growth that is induced by the Ti additiv es. We suggest that the enhanced growth is the result of Ti catalyzed surfa ce reactions. (C) 1999 American Vacuum Society. [S0734-211X(99)02505-6].