Dresden 2009 – wissenschaftliches Programm
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HL: Fachverband Halbleiterphysik
HL 15: C/diamond I
HL 15.4: Vortrag
Dienstag, 24. März 2009, 10:15–10:30, POT 51
Development of ultra nanocrystalline diamond (UNCD) growth rate and surface roughness: a simulation study — •Hadwig Sternschulte1,2 and Ulrich Stimming1,2 — 1nanotum, Technische Universität München, D-85748 Garching — 2Physik Department E19, Technische Universität München, D-85748 Garching
The growth of ultra nanocrystalline diamond (UNCD) with grain sizes of 10 nm and less was simulated by a simple geometrical model: diamond spheres with a fixed diameter are statistically distributed over a flat substrate surface. The number of spheres spread by each simulation cycle are defined by the secondary nucleation rate. Before each start of the simulation, the substrate was covered with diamond seeds whose concentration is described by the primary nucleation rate. The probability to attach a diamond sphere to the bare substrate was set to zero. Distributed diamond spheres which are in contact with yet deposited diamond or with seed nuclei are attached with a probability of one. Two variations of the model are discussed: i) the diamond spheres are attached at the first point of contact (ballistic deposition) resulting in the formation of many voids, and ii) the newly attached diamond spheres are located at the minimum possible z position (solid on solid model) minimising the formation of voids. In this work, a comparison of the early stages of the UNCD growth will be presented. Especially, the development of the minimal film thickness for a continuous closed layer in dependence of the primary nucleation rate, the development of the growth rate with time and of the surface roughness will be discussed with both models and compared with experimental data.