Crystal growth by charged cluster focused on CVD diamond process

Nucleation in the solution or in the gas phase would be difficult to distinguish unless the nuclei grow into visible size during crystal growth. The growth of nuclei tends to be suppressed when the nuclei are charged. Previously, Glasner et al. made a systematic study on crystal growth of KBr in the solution by such block nuclei. Recently, we suggested a charged cluster model in the diamond CVD process, whose concept is very similar to that of Glasner et al. In the model, charged diamond clusters, which contain hundreds to thousands of atoms, are formed in the gas phase in the diamond CVD reactor and become the growth unit of diamond. The high capillary pressure built up inside the nanometer-sized cluster increases the stability of diamond relative to that of graphite. The presence of charge further stabilizes the dielectric diamond over the conducting graphite. The model can explain many unusual phenomena taking place in the diamond CVD process. The presence of the nanometer-sized charged carbon clusters were confirmed by Homann et al. in their combustion study of the C-H-O system under flame conditions where the diamond can be deposited. Crystal growth by charged clusters is suggested to be the general feature in the thin film process where an appreciable amount of charge is produced. (C) 1999 Elsevier Science B.V. All rights reserved.