Erosion of free-standing CVD diamond film

Two kinds of polished and unpolished free-standing films prepared by the d.c. plasma CVD method were impacted by SiC particles to understand erosion mechanism. Erosion damage caused by solid impact was characterized using a surface profilometer, scanning electron microscopy and Raman spectroscopy. A gradual decrease of surface roughness and a sharp reduction of crystallinity were observed for unpolished CVD films with increasing erosion time. It was found that smaller grains of diamond were removed in the early stage of erosion process, and larger grains were eroded with further impingement. By introduction of the regrowth method on polished diamond, a further understanding of erosion mechanism was achieved. Most of the surface fractures were initiated at the grain boundary.