The kinetics of diamond films growth over large area by hot-filament CVD

For the easier scaling up and better growth behavior of diamond films, hot-filament CVD (HFCVD) is considered as the most promising deposition technique compared with the other CVD techniques. However, inhomogeneous nucleation and low growth rate of diamond films are two main barriers to industrial applications for the HFCVD technique. When the relative deposition parameters are fixed at optimized values, the spatial distributions of substrate temperature and gas temperature are calculated by a developed two-dimensional mathematical model based on previous results. In addition, the growth kinetics of diamond films over a large area deposited on silicon (100) is discussed in terms of the simulated results. X-ray diffraction, scanning electron microscopy and Raman spectroscopy were used to characterize the structure and morphology of the films. It is found that under the simulated homogeneous distributions of substrate temperature and gas temperature, the diamond films, although with residual stress, are continuous and uniform with good crystallinity and high quality, the average growth rate is up to 1.8 mm/h. Simultaneously, the dominant morphology of the films is very sensitive to substrate temperature and radical concentrations, which agree well with the earlier simulated results.