Kinetic modeling of the atomic layer epitaxy processing window in group IV semiconductor growth

A kinetic model based on two elementary reaction steps was used for exploring the prospects of atomic layer epitaxy (ALE) on the (100) surface of group IV semiconductors using hydridic source gases. Equating the chemisorption step with depletion of active sites, and the molecular hydrogen desorption step with regeneration of active sites allowed first-principles kinetic modeling of the trends in thin film growth, unencumbered by the lack of mechanistic details of chemisorption and surface decomposition. The combination of first-order depletion and first-order regeneration steps was found to be most favorable for achieving ALE type behavior. The model shows that the ALE window is highly sensitive to the duration of the depletion (chemisorption) cycle suggesting short duration and well defined pulses as the most effective method of source gas delivery.