Influence of substrate holder configurations on bias enhanced nucleation area for diamond heteroepitaxy: Toward wafer-scale single-crystalline diamond synthesis

A simple and effective method to extend the area of bias enhanced nucleation (BEN) for heteroepitaxial diamond growth is introduced. Two-inch substrates are placed on a flat and smooth surface of approximately 3-in. Mo substrate holder and then treated via BEN with or without metal-covered Si plates located right outside of the substrates. It is clarified that not only the plates themselves but also their thickness has a great impact on the BEN area, or in other words, the homogeneity of nucleation density on the substrates. As a result, the epitaxial diamond nucleation is successfully performed on nearly the whole area of a 2-in. Ir/YSZ/Si(001) substrate using the 1 mm thick half-ring plates. For a proof of this concept, finite element method simulations are also performed to investigate the influence of such plates on plasma (electron) density distributions above the substrates. Throughout this study, the significance of substrate holder configurations for the widely accessible wafer-scale diamond heteroepitaxy is revealed.