5 - Diamond Epitaxy, Oriented Growth, and Morphology Evolution

Abstract

This chapter explores the diamond epitaxy, oriented growth, and morphology evolution.The primary difficulty in diamond epitaxy is the small number of materials (Ni, Cu, Fe, Co, Si, and cBN) with suitable crystal structure and lattice constants. The extremely high surface energies of diamond and the existence of inter-facial misfit and strain energies between diamond films and non-diamond substrates constitute the primary obstacles in forming oriented 2D diamond nuclei and single-crystal growth. The high solubility/mobility of C in/on the metals (Fe, Co, Ni), or the formation of an intermediate layer (carbides or graphite) may inhibit the possible development of an orientational, epitaxial relationship between diamond films and the substrates. According to the principle of evolutionary selection, the development of fiber textures is a result of the growth competition between randomly oriented diamond crystals, and the resultant direction of fiber axis coincides with the direction of fastest growth. A detailed understanding of the mechanisms governing the development of crystal orientation, film texture, and morphology is still desirable for the growth of high quality, highly oriented diamond films, and large-area single crystal diamond films.