IN-SITU PULSED RAMAN-STUDY OF THE GROWTH-PROCESS OF DIAMOND FILMS IN A MICROWAVE PLASMA-ASSISTED CVD REACTOR

An experimental set-up designed for in situ Raman analysis during the growth of diamond films in a microwave plasma reactor is described. A gated multichannel detection synchronized with a pulsed YAG laser is u sed to discriminate the Raman signals from the plasma emission and the substrate thermal emission. It is possible to obtain real time inform ation on the growing film at high temperatures (700-1000 degrees C) th rough the plasma. The in situ detection of diamond films during their growth on single crystals of a alumina substrates is presented. We est imate that we are able to detect 15-30 mu g/cm(2) of diamond onto the substrate surface. The line shape of the spectra gives information on the incorporation of non-diamond carbon phases, the integrated intensi ty of the signals on the growth kinetic, and the peak shifts on the pr esence of stress within the growing film.