A Continuous Cellular Automaton for the Atomistic Simulation of Evolving Surface in Anisotropic Etching

A novel analytical solution of continuous cellular automaton (CA) is presented for the simulation of anisotropic wet etching in the fabrication of micro structures. Based on the step flow model, the atomistic characters of surface propagation and classification of the surface sites on etching front have been introduced. An analytical solution for the dependence of the etch rate on orientation is derived in order to transfer the experimental macroscopic etch rates into atomistic removal rates for direct use in the CA model. The removal rates of surface is solved by the non-linear functions of the etch rates by a set of chosen orientations. The simulated etch rates using by CA agree well with the experiments. This improved continuous CA makes possible for the realization of accurate simulations of anisotropic etching in engineering applications.