Etching methodologies in < 111 >-oriented silicon wafers

New methodologies in anisotropic wet-chemical etching of [111]-oriented sil icon, allowing useful process designs combined with smart mask-to-crystal-o rientation-alignment are presented in this paper. The described methods yie ld smooth surfaces as well as high-quality plan-parallel beams and membrane s. With a combination of pre-etching and wall passivation, structures can b e etched at different depths in a wafer. Designs, using the [111]-crystal o rientation, supplemented with pictures of fabricated devices, demonstrate t he potential of using [111]-oriented wafers in microsystem design.