AVS 47th International Symposium
    Surface Engineering Tuesday Sessions
       Session SE-TuP

Paper SE-TuP3
Role of Surface Condition in Diamond Nucleation during Bias-enhanced Nucleation

Tuesday, October 3, 2000, 5:30 pm, Room Exhibit Hall C & D

Session: Poster Session
Presenter: N. Ali, Manchester Metropolitan University, UK
Authors: N. Ali, Manchester Metropolitan University, UK
W. Ahmed, Manchester Metropolitan University, UK
Q.H. Fan, University of Aveiro, Portugal
C.A. Rego, Manchester Metropolitan University, UK
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Thin polycrystalline films of diamond have been deposited on copper substrates using hot-filament chemical vapour deposition (HFCVD) system. It is known that substrate surfaces require some form of pre-treatment prior to diamond CVD. Substrate biasing has been extensively used to enhance diamond nucleation density. Majority of the work published, to date, relating to diamond nucleation by means of bias-enhanced nucleation (BEN) looks at either negatively or positively biasing substrates such as silicon where the surface biased is smooth. However, there is very little work been carried out which investigates the effect of surface roughness and surface impurities on diamond nucleation during the BEN process. We negatively bias polished copper substrates, where the polishing materials used were diamond paste, diamond powder and silicon carbide. Our preliminary results have shown that by amalgamating surface polishing with biasing there is a definite enhancement in the overall nucleation density with all the commonly used polishing materials. We observed that both surface roughness and polishing material residues seeded into the copper substrates play a critical role in diamond nucleation during the BEN process. The nucleation densities were calculated from SEM images and the surface roughness values were obtained from AFM analysis. Furthermore, the quality of the diamond grains was gauged using Raman spectroscopy.