Bias-enhanced diamond nucleation on silicon—a TEM study

Abstract

The bias-enhanced nucleation and early growth of diamond on (100) silicon by microwave plasma-enhanced chemical vapour deposition (MPCVD) from a CH4H2 gas mixture were investigated by transmission electron microscopy (TEM). Hillocks containing β-SiC, diamond and amorphous components are the most prominent features at the substrate surface after bias-enhanced nucleation. The hillocks are formed not only by the deposition of carbon, but also by the re-deposition of Si etched from the substrate surface. In between the hillocks, β-SiC clusters, with a distinct texture parallel to the heteroepitaxial orientation, are formed at the interface between the silicon substrate and a thin amorphous layer. During subsequent diamond growth, only the hillocks act as nucleation sites.