OPTICAL-EMISSION SPECTROSCOPY OF THE PLASMA DURING MICROWAVE CVD OF DIAMOND THIN-FILMS WITH NITROGEN ADDITION AND RELATION TO THE THIN-FILMMORPHOLOGY

It is common knowledge that the presence of gas impurities such as nit rogen during microwave plasma assisted chemical vapour deposition of d iamond can drastically affect the film morphology and even favour the growth of oriented textured films. it was shown previously that diamon d films could be grown with various preferred orientations depending o n the fraction of nitrogen present in the process gas mixture. In this work, we show how the methane and nitrogen fractions in the feed gas can alter the morphology of the diamond film deposited at high substra te temperature (1600 K). The domain of high substrate temperatures (>1 300 K) has not yet been widely investigated and offers the opportunity of growing diamond films with other textures and morphologies with re spect to their counterparts grown at lower temperatures. Optical emiss ion spectroscopy is applied to study the spatial distribution of atomi c hydrogen, CN and Ca emitting radicals from the substrate surface to the bulk plasma. Scanning electron microscopy and X-ray diffraction ar e used, respectively, to identify the different diamond film morpholog ies and to establish the preferred growth orientations ranging from {1 11} to {100} textured films. (C) 1997 Elsevier Science S.A.