Modelling of silicon hydride clustering in a low-pressure silane plasma

A new silicon hydride clustering model was developed to study the nucleation of particles in a low-temperature silane plasma. The model contains neutral silanes, silylenes, silenes and silyl radicals as well as silyl and silylene anions. Reaction rates were estimated from available data. Simulations were carried out for typical discharge parameters in a capacitive plasma. It was shown that the main pathway leading to silicon hydride clustering was governed by anion-neutral reactions. SiH2 radical insertion was found to be important only in the initial stages of clustering, whereas electron-induced dissociations were seen to lead to dehydrogenation. Increased ion density (radiofrequency power density) leads to faster clustering due to increased formation of reactive radicals.