Silicon epitaxial growth on the Si(001)2×1 surface from silane using dynamic Monte Carlo simulations

Abstract

Dynamic Monte Carlo (DMC) simulations are carried out on silicon (001)2×1 surface under 100% silane gas chemical vapor deposition condition as a function of surface temperature (600–800° C) and pressure (6 and 12 mTorr). The reactant on the surface from gas-phase is assumed to be the silane molecule. The rates and probabilities of surface reactions are determined a priori by recent ab initio calculation results in the literature. The DMC method can reveal not only the short-time microscopic mechanism but also predict the macroscopic phenomena such as deposition. The calculated growth rate and Arrhenius activation energy of growth depending on temperature show good agreement with experimental results. The results suggest that the low activation energy regime above 700 °C is associated with a process controlled by silane dissociative adsorption. In contrast, the higher activation energy regime below 700 °C is supposed to be governed by hydrogen desorption. The periodic change of surface structure that is similar to reflection high-energy electron diffraction intensity oscillation in the process of molecular beam epitaxy is observed. The periodic behavior results from the repeat of a series of hydrogen desorption, silane adsorption, surface incorporation, and adatom diffusion on the growing surface.