Diamond films have been successfully prepared using hot-filament CVD, microwave plasma-assisted CVD, DC arc plasma jet CVD, and other methods in recent decades. However, our understanding of the growth mechanism of metastable diamond is still vague. In order to find the answer to why diamond films can be deposited from different gas sources by different synthesis techniques, scientists have studied the nucleation and growth process of diamond film from the two aspects of surface reaction and gas-phase reaction.
It is found that diamond nucleation density on the heterosubstrates can be greatly increased by the mechanical damage, the predeposited buffer layer, and the bias-enhanced nucleation methods. Of these methods the bias-enhanced method brings the best hope of realizing the heteroepitaxial growth of diamond films. The results of cross-section HRTEM imply that the diamond nucleation site is important to the heteroepitaxial growth of diamond. Under the CVD conditions, two growth modes, i.e., layer growth and spiral growth, were found in the growth process of diamond. In addition, substrate material selections with some novel considerations were attempted to deposit high-quality and epitaxial diamond films.
Many in situ diagnostic techniques have been employed for the growth environment evaluation, such as molecular beam mass spectroscopy, laser-induced fluorescence, and optical emission spectroscopy. These techniques can provide direct, quantitative, or semiquantitative information for a large number of stable and radical gas species about their energy and spatial distribution. With in situ diagnostics, we can efficiently correlate gas phase conditions with film properties such...
TABLE OF CONTENTS 
