Search

The article reports combined effects of Ar addition and substrate bias on the grain size, microstructure, and growth rate of the diamond films prepared in microwave plasma-enhanced chemical vapor deposition. The nanocrystalline diamond (NCD) films with grain size of 50-100 nm, characterized by Raman spectra, scanning and transmission electron microscopy, were produced at 90-99 vol% Ar concentration under -50 V substrate biasing. The growth rate of the NCD films was 0.7-0.8 μm h[SUP-l], larger apparently than those grown by only Ar addition or by substrate bias effect alone. The NCD formation by various mechanisms is discussed, and a revised C[SUB2] insertion mechanism by the promotion of H[SUP+] ions is proposed to interpret the higher growth rate of the NCD films. [ABSTRACT FROM AUTHOR]

The influence of negative substrate bias on the crystallinity, morphology, and growth rate of the diamond films deposited using microwave plasma-enhanced chemical vapor deposition in 1% CH[sub 4]/H[sub 2] plasma were investigated. The nanocrystalline diamond films were produced exclusively under the biasing at -250 V. With -50 V biasing, faceted (111) microcrystalline diamond films at higher growth rate than no-bias samples were produced. When the biasing between - 100 and -200 V, faceted (100) diamond films with decreasing grain size were favored, and the growth rates were gradually reduced along with the increasing biasing. The results indicate that the etching efficiency of H[sup +] ions is enhanced with the increasing kinetic energy obtained from the increasing bias voltage. On the other hand, CH[sup +, sub x] ions at -250 V biasing would have sufficient energy to perform the ion subplantation model to grow the nanocrystalline diamond films by bias-enhanced nucleation. [ABSTRACT FROM AUTHOR]