Monte Carlo simulation of diamond growth by methyl and acetylene reactions

A dynamic Monte Carlo technique was applied to gas-surface reactions simulating diamond growth under chemical vapor deposition. A combined methyl-and-acetylene reaction mechanism was assumed, where the additions of methyl radicals and acetylene molecules are allowed to occur only when no steric interferences arise. The sterically resolved computations demonstrate nonlinear kinetic coupling: methyl and acetylene additions occur simultaneously and interdependently on each other−adsorption of CH3 creates sites for C2H2 addition, and addition of C2H2 creates sites for CH3 adsorption. It is also shown that the incorporation of acetylene by three-center additions only, irreversible on physical grounds, is capable of explaining the rate of diamond growth, thus dismissing the argument of reaction reversibility advanced against our proposed mechanism of acetylene addition.