Evaluation of the Step Flow Etching Rate Model Based on Atomic Clusters of Monocrystalline Silicon

Monocrystalline silicon is widely used in microelectromechanical systems (MEMS), and analyzing the anisotropism of etching rates of monocrystalline silicon is the basis for refining the wet etching technology of monocrystalline silicon. In this paper, the atomic cluster-step flow (AC-SF) etching rate model of monocrystalline silicon is established, which realizes the accurate calculation of etching rates of lattice planes. First, based on the complicated characteristics step-terrace frameworks of lattice planes of monocrystalline silicon, the atomic cluster is taken as the minimal module of the atomic structures of lattice planes, and the division of atom cluster categories is performed, which greatly reduces the complexity for calculating etching rates of lattice planes of monocrystalline silicon. Then, the removal probabilities of external atoms in atom clusters are calculated by the Monte Carlo method to verify the rationality of the removal sequence of different categories of atomic clusters. Finally, a general formula for the calculation of etching rates of lattice planes is derived based on the whole removal procedure of atomic clusters of lattice planes, and the validity of the proposed atomic cluster-step flow (AC-SF) etching rate model of monocrystalline silicon is verified based on small rate errors between the calculative rates and experimental rates.