Influence of process parameters on the size of the bias-nucleated area for diamond deposition with plasma-enhanced chemical vapour deposition

Diamond deposition experiments on polished silicon were made with microwave plasma chemical vapour deposition using bias-enhanced nucleation. The aim was to investigate the size dependence of the nucleated area on the process parameters. The nucleation density distribution across the border of nucleated/not nucleated and the effects observed with the bias current are discussed by means of a model given in the literature. The dependencies of the size of the prenucleated area on substrate temperature, pressure, and bias voltage are described and discussed. With sufficiently high bias voltage, for example -300 V, a 3 '' wafer can be prenucleated throughout the whole area. At low substrate temperatures the bias prenucleation cannot be used as both nucleation density and nucleated area are too small for practical applications.