AXIAL DISTRIBUTION OF EMISSION AND RATE OF DEPOSITION OF DIAMOND-LIKEFILM IN RF DISCHARGES IN CH4

Spatial distribution of the deposition rate of diamond-like thin films inside a r.f, discharge was studied experimentally. A thin optical fi ber was inserted along the axis of the discharge which made negligible perturbation on the discharge itself, Deposited film thickness along the fiber was determined by using a scanning electron microscope and u niform and stable films up to 24 mu m thick were made over periods of up to 19 h. The spatial distribution of deposition resembled the diffu sion profile and from the comparison of its second derivative and the spatial distribution of emission it was found that the deposition prec ursor does not react with the ground-state molecules. From the analysi s of available chemical kinetics and transport data for methane discha rges it was found that the deposition precursor is CH3 radical. Spatia l distribution of emission was obtained using a CCD camera with interf erence filters. (C) 1997 Elsevier Science S.A.