Quantitative modelling of nucleation kinetics in experiments for poly-Si growth on SiO by hot wire chemical vapor deposition

We apply a rate-equation pair binding model of nucleation kinetics to the nucleation of Si islands grown by hot wire chemical vapor deposition on SiO substrates. The grain size of poly-Si films increases with H dilution, which is attributed to atomic H 2 2 etching of Si monomers rather than stable Si clusters during the early stages of nucleation. The nucleation density increases sublinearly with time at low coverage, implying a fast nucleation rate until a critical density is reached, after which grain growth begins. The nucleation density decreases with increasing H dilution (H :SiH ) due to etching, and with increasing temperature, 2 2 4 due to enhanced Si monomer diffusivity on SiO . From temperature-dependent measurements, we estimate the activation energy 2 for surface diffusion of Si monomers on SiO to be 0.47"0.09 eV. Simulations of the temperature-dependent supercritical cluster 2 density lead to an estimated activation energy of 0.42"0.01 eV and an estimated surface diffusion coefficient prefactor of 0.1"0.03 cm ys. 2 2003 Elsevier B.V. All rights reserved.