Modeling of Particle Growth in RF Silane-Helium Plasma

A model for an early stage of particle growth is developed in order to investigate the process of particle growth around the electrode sheath boundary observed experimentally in an rf silane-helium plasma. In this model, it is assumed that formation of higher silane radicals produced by reaction chains of short-lifetime radicals and fast accretion of the higher silane radicals may lead to particle growth. Negatively charged particles are not taken into account in this model. The spatial distribution of the short-lifetime radicals such as SiH 2 generated in the rf silane-helium plasma is obtained using a fluid model. Using the density of SiH 2 as an initial condition, the spatiotemporal evolutions of the particles having up to 100 SiH n s are calculated. This indicates that short-lifetime higher silane radicals are responsible for particle growth in the rf silane-helium plasma.