Optical properties of plasma species absorbed during diamond deposition onsteel

Diamond thin films have been deposited directly on stainless steel substrat es at low pressure and low temperature conditions over the range of methane (CH4) to hydrogen (H-2) ratios of 4% to 9% using electron-cyclotron-resona nce microwave plasma-assisted chemical vapor deposition (PACVD) technique. In situ Fourier transform infrared spectroscopy, employed in a reflection-a bsorption geometry (FTIRRAS), and optical emission spectroscopy have been u sed to study the plasma species adsorbed on the substrate surfaces as well as the species above the substrates surfaces both before and during the nuc leation and film growth. It is demonstrated that these techniques can provi de useful information on the early stages of diamond growth. When correlate d with film properties measured by Raman spectroscopy and scanning electron microscopy, the results from FTIRRAS indicate that the absorption of the g raphitic and diamond phases are related to the ratio of CH4 to H-2 and can be identified at the early stages of film growth. (C) 2000 American Institu te of Physics. [S0021-8979(00)05718-2].