Theoretical Study for Characteristic Surface Morphologies Fabricated by Anisotropic Chemical Etching

The technique of the anisotropic wet chemical etching had turned into one of the widely used processes for manufacturing the functional materials in microelectromechanical systems. To better understand the issues of growth mechanisms for the characteristic surface morphologies during an anisotropic chemical etching, in this study the formation and evolution of surface structures were investigated by numerical simulation methods. A chemical etching model was established on the basis of chemical reaction and atomic diffusion. Affecting by the anisotropy of the crystalline structure and etching rate, various featured surface morphologies, including the rippling surface, cusp-like hillock, and nano-pyramid, were numerically developed in accordance with the etching conditions. These characteristic structures were also in well agreements with the corresponding experiments. From the theoretical point of view, the surface morphologies were critically influenced by the kinetic factors of the anisotropic etching rate and the atomic diffusion. With the enhancement of theoretical work in the formation mechanism for the anisotropic chemical etching, the practical technique would possess a more competitive advantage for the wide applications in the fields of the functional materials fabrication.