PLASMA CHEMISTRY IN SILANE GERMANE AND DISILANE GERMANE MIXTURES

A detailed kinetic study of silane-germane glow discharges is presented. Stable gas decomposition and production rates have been measured using mass spectrometry and a kinetic model for the plasma chemistry is developed. It is found that germane depletes about four times faster than silane, nearly independently of their relative fractions. Germane is found to be much more reactive than silane with silylene, germalyn, and atomic hydrogen, and the silylene-germane reaction leads in large part to film rather than stable gases. The spatial characteristics of the discharge are studied using optical emission and fiber deposition profiles. From these it is deduced that the present, low-power discharge operates in a "hybrid" alpha-gamma regime, and that ion effects are important near the electrodes.