A MICROSTRUCTURAL AND MORPHOLOGICAL-STUDY OF DIAMOND CRYSTALS AND FILMS ELABORATED BY MICROWAVE PLASMA-ASSISTED CHEMICAL-VAPOR-DEPOSITION

In this work, morphological and microstructural characterization of co ntinuous films and isolated crystals of diamond obtained by microwave plasma-assisted chemical vapour deposition was carried out using trans mission electron microscopy and scanning electron microscopy to correl ate the diamond morphology and nucleation density with physical parame ters of the deposition procedure such as gas composition (argon or oxy gen additions to a CH4-H-2 system), temperature variations and pretrea tment of the silicon substrate. This study was carried out using a par ticular plasma configuration which allows temperature and plasma densi ty gradients. We point out that good quality diamond film can be achie ved by a compromise between a low substrate temperature (obtained by d ecreasing the microwave power) and good plasma reactivity (obtained by adding gases such as O2 or argon). In order to obtain a continuous di amond film, it is necessary to scratch the substrate with abrasive par ticles; we demonstrate that the nucleation density strongly depends on the nature of these particles.