Effects of annealing process on film surfaces grown by molecular beam epitaxy growth model with arrhenius law

Abstract

Presently many researches focus on how to minimize roughness of a film surface. An annealing process is one of the most promising techniques which are used to reduce roughness of the grown surface after the deposition of an atom has ended because it provides thermal energy for atoms on the substrate to break bonds formed during its deposition and diffuse to other positions. Despite being commonly used experimentally, the annealing process is seldom included in growth simulation studies. The objective of this work is to study the role of annealing process on a film surface grown by Molecular Beam Epitaxy model when the law governing the diffusion rate in simulations follows the Arrhenius law. The simulation results agree with the experimental results that the film surface is smoother when the annealing process is applied. Moreover, studies of the film surface morphology, the interface width, and the correlation functions show that the roughness of the interface decreases as the annealing temperature is increased. This is because the chance for an atom to diffuse to positions with large coordination numbers increases significantly with temperature. However, at high temperature, the desorption rate of an atom is higher and the desorption process, which is usually neglected in simulations, can become significant. For this reason, we study the effect of desorption process on the film surface by comparing statistical properties of films grown with and without desorption of atoms. The results show that when the annealing temperature is above 900 K, global statistical properties of the film are not significantly affected by the desorption of atoms but the morphologies and local properties are distinguishable.