ABSTRACT
In Situ infrared Cavity Ring Down Spectroscopy of a capacitively coupled RF Ar/SiH4 dusty plasma.
J. Remy, A.H.F.M. Baede, C.H.J.M. Groothuis, W.W Stoffels, G.M.W. Kroesen , TU/e Eindhoven, Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven, The Netherlands – EU
Silane radicals are thought to play important roles in the chemical processes leading to the growth of micro sized particles in capacitively coupled RF Ar/SiH4 dusty plasmas. In order to better understand the actual formation of those particles, it is necessary to monitor their composition during the growth process. Therefore, Cavity Ring-Down Spectroscopy (CRDS), using a cw laser diode operating in the mid-infrared wavelength range, has been performed. CRDS offers the possibility of absolute density measurements, common to all absorption techniques, but it has a much better detection limit. This allows accurate measurements of reaction products and radicals, which, due to their reactive nature, have a low density in the RF plasma. A novel mode detuning technique has also been used to investigate the dynamics of the radicals [1]. The ring-down results point out a detection range for the absorbance of those radicals in the order of 10-5. This diagnostic technique provides valuable information that helps elucidating the particles formation process.
