Investigation of growth mechanisms of clusters in a silane discharge with the use of a fluid model

A one-dimensional fluid model was developed to study the formation of dust nanoparticles in a low-pressure capacitively coupled radio-frequency silane (SiH₄) discharge. In this model, the particle balances, the electron energy balance, and the Poisson equation are solved self-consistently. A set of 66 species, including neutrals, radicals, ions, and electrons, are incorporated. A total of 111 reactions are described in the model, comprising electron impact reactions with silanes, neutral-neutral, and ion-neutral reactions. Plasma conditions are typically those used for the deposition of amorphous silicon (a-Si:H). The model includes the formation of silicon hydrides (Si_nH_m) containing up to 12 silicon atoms. Anion-induced chain reactions are considered to be the main pathway leading to cluster formation.