Handbook of Silicon Based MEMS Materials and Technologies

24.2. Beyond Faceting: Atomistic Phenomena

In spite of the widespread and technological maturity of anisotropic etching for applications, the complexity of the process—involving chemical and electrochemical reactions sensitive to a multitude of parameters—has traditionally prevented a satisfactory understanding of this technique. Experimental, theoretical, and computational work in the last two decades has led to an important change of mentality. Although the etch rate anisotropy leads to faceting, the description of anisotropic etching as the propagation of a collection of crystallographic planes is an oversimplification. Anisotropic etching is not considered anymore as a macroscopic process involving the propagation of an evolving facetted ...