Theoretical study of elementary surface reactions in silicon epitaxial growth

Abstract

The growth of silicon via gas-source molecular beam epitaxy (GSMBE) and chemical vapor deposition (CVD) involves sequential decomposition of precursors such as silane and disilane, migration of surface species, recombination and desorption of hydrogen. Experiments found that the recombinative desorption of hydrogen and the dissociative adsorption of precursor are particularly important during silicon epitaxial growth. In this work, we investigated these two elementary surface reactions using pseudopotential planewave density functional method. We examined the reaction mechanisms by calculating the energy barriers for these surface reactions. In addition, the interaction of hydrogen with the stepped Si(100) surface are also explored. We found that the presence of step has a significant influence on silicon growth. Our results provide new insights into the microscopic processes during silicon expitaxial growth.