Coalescence as a key process in wafer-scale diamond heteroepitaxy
V. Lebedev, Jan Kustermann, Jan Engels, Jürgen Weippert, V. Cimalla, Peter Knittel, Lutz Kirste, Christian Giese, Patricia Quellmalz, Andreas Graff, Jan Jeske
Abstract
Due to fascinating physical properties powered by remarkable progress in chemical vapor deposition of high-quality epilayers, diamond thin films attract great attention for fabrication of nitrogen-vacancy-based solid-state spin systems capable of operating in ambient conditions. To date, diamond heteroepitaxy via bias-enhanced nucleation is an unavoidable method for reliable wafer-scale film manufacturing. In this work, we analyze the coalescence phenomena in nitrogen doped, heteroepitaxial diamond epilayers, with a particular focus on their specific role in the annihilation of macroscopic crystal irregularities such as grain boundaries, non-oriented grains, and twinned segments. Here, we also report on the growth mechanism for the “primary” crystal orientation along with a predominant formation of two different types of boundaries highlighting the {011}-type as a main source of the crystal lattice irregularities.