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

Abstract

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 substantially enhanced by using a mixed slurry (Di/Ti) compared to abrasion with a diamond slurry solely. It was also determined that, under the ultrasonic agitation conditions used in this work, the addition of titanium particles to the abrasive suspension does not affect the quantity of embedded diamond growth centers, nor does it alter their chemical character. Rather, the Ti particle additives are active during the initial stages of deposition. Ion implantation experiments show that diamond homoepitaxially grows on diamond residues, and that Ti residues do not serve as nucleation centers. The annihilation of diamond growth centers prior to stable substrate formation is attributed to hydrogen etching, while the effect of thermal annealing is negligible. These experiments show that Ti residues do not prevent the etching of diamond debris. We therefore conclude that the increase in DPD is related to an enhancement in diamond growth that is induced by the Ti additives. We suggest that the enhanced growth is the result of Ti catalyzed surface reactions.