Pulsed laser surface modifications of diamond thin films

In view of practical applications requiring diamond films, plates and membranes with very smooth surfaces, ArF excimer laser polishing treatments were applied to thin (30 mm) diamond films grown by CVD on silicon substrates. The as-prepared diamond surfaces and the laser-treated parts of the samples were characterised by SEM analysis, Raman and micro-Raman spectroscopy. The presence on the laser-treated surface of a thin amorphous carbon layer responsible for the higher surface electrical conductivity and for the different optical reflectivity properties was evidenced. Using confocal micro-Raman spectroscopy a comparative depth profile analysis of the phase quality, below the surface in different regions of the films, was carried out. After short (10 min) treatment by H2 plasma etching in the CVD chamber the graphitic top layer was completely removed from the samples.