DIAMOND GROWTH DURING BIAS PRETREATMENT IN THE MICROWAVE CVD OF DIAMOND

We have investigated the spatiotemporal development of the plasma duri ng the bias pre-treatment that precedes the chemical vapour deposition (CVD) of diamond and the chemical composition, the identity of carbon modifications, and the topography of the substrate surfaces after sel ected stages of the biasing. The methods employed were X-ray photoelec tron spectroscopy (XPS) and Raman spectroscopy as well as scanning ele ctron microscopy (SEM). Areas of high diamond nucleation density were identified at each stage by interrupting the bias pre-treatment, switc hing to growth conditions and screening for diamond crystals after gro wth for Ih with SEM. After about 10 min the biasing alone yields an al most pure diamond surface as judged by the loss features in XPS althou gh neither Raman spectroscopy nor SEM give any indication thereof. In particular, for the growth of highly oriented textured diamond films, the stage at which the biasing is stopped is crucial since prolonged g rowth of diamond under biasing conditions destroys the initial orienta tion of the diamond nuclei.