Dynamics and control of thin film surface microstructure in a complex deposition process

In this work, a complex deposition process, which includes two types of macromolecules whose growth behaviors are very different, is investigated. This deposition process is influenced by both short- and long-range interactions. The study of this process is motivated by recent experimental results on the growth of high-κ dielectric thin films using plasma-enhanced chemical vapor deposition. A multi-component kinetic Monte-Carlo (kMC) model is developed for the deposition. Both single- and multi-component cases are simulated and the dependence of the surface microstructure of the thin film, such as island size and surface roughness, on substrate temperature and gas phase composition is studied. The surface morphology is found to be strongly influenced by these two factors and growth regimes governed by short- and long-range interactions are observed. Furthermore, two kMC model-based feedback control schemes which use the substrate temperature to control the final surface roughness of the thin film are proposed. The closed-loop simulation results demonstrate that robust deposition with controlled thin film surface roughness can be achieved under a kMC estimator-based proportional integral (PI) feedback controller in the short-range interaction dominated growth regime, while a kMC model-predictive controller is needed to control the surface roughness in the long-range interaction dominated growth regime.