Insights into the ion-assisted nucleation of diamond on silicon

Abstract

The ion-assisted nucleation of diamond was studied in a microwave plasma chemical vapor deposition system to gain insights into the processes controlling this phenomenon. The dependence of the nucleation density on bias voltage and temperature, as well as experiments with an electrically isolated substrate, are consistent with an ion bombardment mechanism for diamond nucleation. However, the growth of these nuclei is dominated by neutral species rather than ions. Measurements of the bias current under various conditions also provide details on the roles of the incident ion flux and substrate electron emission during this process. Furthermore, Monte Carlo simulations of the ion energy distribution at the substrate are compared to experimental measurements. Preferential sputtering, thermal spike, and carbon subplantation nucleation mechanisms are assessed based on the experimental and modeling results.3354

Diamond nucleation enhancement by direct low-energy ion-beam deposition

“…Since the thermal spikes occurred from the beginning of the ion bombardment process, as a result nanocrystalline diamond would have appeared much earlier at smaller ion doses. The subplantation model, first suggested by Lifshitz and co-workers 36,37 and used to explain the BEN process, 41,42 is found more suitable to describe our present experiments. During ion bombardment, the energetic hydrocarbon ion arrives and enters the substrate surface; and eventually loses its energy in overcoming the penetration threshold potential.…”