Surface modifications and first stages of heteroepitaxial diamond growth on iridium

Nucleating diamond on iridium buffer layers by the bias enhanced nucleation procedure causes a characteristic roughening of the Ir(001) surface. Shape, dimensions and crystallographic alignment of the formed structures can be controlled by the methane concentration in the plasma. Different processes are discussed which contribute to their formation. After a short growth step, epitaxial diamond crystals are found with areal densities of 10(11) cm(-2). Transmission electron microscopy images show that coalescence of these grains starts already after few minutes of growth at a film thickness of 10 nm. By using epitaxial iridium films consisting of a mixture of (001)- and (111)-oriented iridium domains, it was possible to show that (001) and (111)oriented epitaxial diamond grains can be nucleated with similar high densities under exactly identical process conditions. (C) 2003 Elsevier B.V. All rights reserved.