Diamond nucleation on iridium buffer layers and subsequent textured growth: A route for the realization of single-crystal diamond films

It is shown that diamond nucleation on iridium buffer layers followed by an appropriate textured-growth step offers a viable way to realize single-cry stal diamond films. Bias-enhanced nucleation on iridium layers results in h eteroepitaxial diamond films with highly improved alignment. By a subsequen t textured-growth step, the mosaicity can be further reduced for tilt as we ll as for twist in sharp contrast to former experiments using silicon subst rates. Minimum values of 0.17 degrees and 0.38 degrees have been measured f or tilt and twist, respectively. Plan view transmission electron microscopy of these films shows that, for low thicknesses (0.6 mum and 8 mum), the fi lms are polycrystalline, consisting of a closed network of grain boundaries . In contrast, at the highest thickness (34 mum) most of the remaining stru ctural defects are concentrated in bands of limited extension. The absence of an interconnected network of grain boundaries shows that the latter film s are no longer polycrystalline. (C) 2001 American Institute of Physics.