X-ray photoelectron spectroscopy study of substrate surface pretreatments for diamond nucleation

The effects of surface pretreatments on the nucleation of diamond on silicon substrates have been studied by quantitative x-ray photoelectron spectroscopy measurements. It was found that methods of surface pretreatments including ultrasonic abrasion, scratching, and dc biasing all introduced a substantial amount of carbon species to the substrate surface which was the primary reason for the enhancement of diamond nucleation. Both the scratching and biasing processes formed carbide on the Si surface which also facilitated diamond nucleation. In addition, the biasing process reduced and suppressed the formation of oxide which further contributed to the enhanced nucleation density of diamond. This analysis is consistent with the experimental data of nucleation densities of diamond on the differently pretreated substrate surfaces both observed in this study and found in the literature.