COLUMNAR CVD DIAMOND GROWTH-STRUCTURE ON IRREGULAR SURFACE SUBSTRATES

Columnar grain structure is always observed in CVD-diamond growth and is an important parameter to identify the morphology of thin and thick films. Structure defects, aspects of onset nucleation and film growth mechanisms can also be related to columnar growth. In this work we fo cused our attention on the columnar structure of CVD-diamond grown on irregular surfaces. We observed that there is a relationship among cur vature radius of the substrate surface, the spread of the column volum e and the growth rate of the diamond film. Growth rates on spherical s urfaces of around 0.5 mm curvature radius have been observed to be up to three times bigger than the growth rates on planar surfaces. Also, the grain size distribution on planar and on the corner surfaces as a function of the growth rate has been studied. Characterization with sc anning electron microscopy (SEM) and Raman scattering spectroscopy (RS S) has been performed.