Kinetic Monte Carlo Simulation of Plasma Deposition of Silicon Thin Films

We report results from kinetic Monte Carlo simulations of plasma deposition of silicon thin films under conditions that render the SiH$_{3}$ radical the dominant deposition precursor. The transition probabilities for the various kinetic events accounted for in the simulations are based on first-principles density functional theory (DFT) calculations of the corresponding optimal pathways on the H-terminated Si(001)-(2$\times $1) surface and on molecular-dynamics simulations on hydrogenated amorphous silicon film surfaces. The relevant surface transport and reaction processes include SiH$_{3}$ diffusion, SiH$_{3}$ chemisorption and insertion into Si-Si bonds, surface H abstraction reactions, surface hydride dissociation reactions, as well as SiH$_{4}$ and Si$_{2}$H$_{6}$ desorption into the gas phase. Surface etching is predominantly observed over the 373-640 K temperature range. The surface compositions obtained are in good agreement with experimental measurements on films deposited under similar growth conditions. At 500 K, surface SiH$_{2}$ formed by surface trihydride dissociation reactions is the dominant surface hydride species.