Elastic Energy Relaxation in the Chemical Reaction of CO with Single-Crystalline Silicon during Coordinated Substitution of Atoms

Abstract

This study provides a detailed microscopic description of the chemical transformation of a silicon crystal into a silicon carbide crystal via reaction with carbon monoxide gas at the Si(111) surface. This was done using density functional theory in the spin-polarized PBE approximation. All intermediate (adsorption) states and the single transition state were identified using the NEB method. It was shown that the transition state is an Si–O–C triangle with bond lengths of 1.94, 1.24, and 2.29 Å. Additionally, the energy profile of this chemical reaction was calculated. The presence of dangling bonds was found to generate both electric and magnetic fields during the reaction. According to the results, the relaxation of elastic energy provides efficient ordering of the growing crystals by weakening the bonds of the certain atoms. That is why the (111) surface is the optimal for silicon carbide growth by this method for semiconductor applications.