ABSTRACT
In Situ infrared optical measurements of gas properties in a capacitively coupled rf Ar-SiH4 plasma.
J. Remy, G. Dingemans, G. M. W. Kroesen, W. W. Stoffels , TU/e Eindhoven, Den Dolech 2, P.O. Box 513, 5600 MB Eindhoven, The Netherlands – EU
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, in situ Fourier Transform infrared absorption spectroscopy (FTIR) and cavity ring-down spectroscopy (CRDS) in the mid-infrared wavelength range have been performed. FTIR, on the one hand, has been used to study the SiHx dust particles that are formed and suspended in the plasma. Results particularly indicate time and pressure dependency of the solid-state vibrational absorptions of the SiH and SiH2 bands. FTIR has also helped us determine the silane dissociation and its evolution after plasma ignition. CRDS, on the other hand, has used a novel mode detuning technique to investigate the dynamics of the radicals. Some preliminary ring-down results point out a detection range for the absorbance of those radicals in the order of 10-5. These two diagnostic techniques provide information that help elucidating the particles formation process.
