Detection of Si nanoclusters by x-ray scattering during silicon film deposition by mesoplasma chemical vapor deposition

A laboratory-scale small angle x-ray scattering (SAXS) system was designed to detect free silicon nanoclusters generated in the gas phase during silicon film deposition by an inductively coupled mesoplasma chemical vapor deposition system at different $SiH4$ partial pressures and rf powers. Analysis of the SAXS profiles collected from the vicinity of the plasma-substrate boundary layer has revealed the presence of a polydisperse system of spherical scatterers having a loosely bound structure with around $2–3nm$ in size. A small amount of larger-sized nanoclusters was found to form as the rf power decreased, and emergence of such large nanoclusters was seen to be associated with the transition from an epitaxial to agglomerated microstructure of the films so deposited.