anisotropic silicon etching is a key technology for the fabrication of micromechanical devices. it allows for the precise three-dimensional structuring of miniature sensors and actuators in an ic compatible way. the three main properties that make this technique so widely applicable are the dependence of the etch rate on the crystal direction, on the dopant concentration, and on an externally applied electric potential. the crystallographic anisotropy provides the means for a very precise lateral machining of a device by proper alignment of structural contours with either fast or slow etching crystal planes. so far, several papers have been published providing experimental data and models for describing specific aspects of the etching mechanism. within the reported article, an attempt is undertaken to provide a general unifying model for all alkaline anisotropic silicon etchants. furthermore, several aspects regarding the application of anisotropic etchants for the fabrication of micromechanical devices are discussed. (orig./rhm) (copyright (c) 1990 by fiz. citation no. 90:081831.)