Kinetic Modeling of Grain Growth in Polycrystalline Silicon Films Doped with Phosphorus or Boron

The effects of phosphorus and boron doping on normal grain growth in LPCVD-deposited Si films were investigated using transmission electron microscopy (TEM) in conjunction with Hall mobility measurements. While boron doping had little effect, phosphorus doping was found to substantially enhance grain growth. It is argued that phosphorus-enhanced grain growth occurs due to an increase in the grain boundary atomic mobility. A kinetic model is suggested which can be used to quantitatively predict the observed enhancement over wide ranges of temperature and doping. In this model, it is assumed that grain growth occurs through a diffusive process and/or a nondiffusive process. Phosphorus doping enhances the diffusive process by increasing the number of charged vacancies and therefore the total number of vacancies.