Pulsed Biased Growth of Nanocrystalline Diamond by Hot Filament Chemical Vapour Deposition

For many industrial applications such as biomedical instruments, optical devices and microelectromechanical systems, the control of the film structure, crystallinity and morphology is of critical importance. The crystallite size, orientation and surface roughness have a profound effect on the mechanical, optical and electrical properties of the films and therefore the final product performance. In order to reduce the crystallite size and surface roughness, inert gases were added to the methane and hydrogen mixture during chemical vapour deposition of nanocrystalline diamond films. In addition, the results on the influence of pulsed biasing on the morphology of these films are reported. Bias voltages in the range -300-0 V were investigated. Increasing the bias voltage significantly alters the crystallite size and morphology of the deposited films. Raman spectroscopy, SEM and atomic force microscopy were used to characterise the nanocrystalline diamond films. SE/501