Single step electrochemical etching in ammonium fluoride

This paper presents a new technique of micromachining using single step ele ctrochemical etching in an ammonium fluoride based etchant. This etching te chnology is to fabricate 3-D structures in single crystal silicon by a comb ination of anisotropic and isotropic etching mode. The etch rate and morpho logy of the etched surface are investigated for the etch parameters (etchan t concentration, current density). Optimization of these parameters mak:es it possible to make free standing beams. Using the ammonium fluoride as the etchant, aluminium survives the etching. (C) 1999 Elsevier Science S.A. Al l rights reserved.