Silicon anisotropic etching in alkaline solutions IV - The effect of organic and inorganic agents on silicon anisotropic etching process

Silicon anisotropic etching process in organic and inorganic solutions has been studied. Experimental results on silicon etching in KOH and TMAH solutions with and without IPA addition have been presented. Etching rate curves versus solution concentration were plotted for different crystallographic planes with special emphasis on high-indexed ones. A comparison of our own experimental results with the results of other authors, concerning silicon anisotropic etching process in hydroxides of other metals from the first group of periodic table, revealed that their ions and molecules contained in the solution play an important role in the process and influence its anisotropy. The observations led us to some general conclusions regarding physical and chemical phenomena associated with the silicon anisotropic etching. We have suggested that the lowering of etching rates is connected with adsorption of cations and organic additions on some crystallographic planes. (C) 2001 Elsevier Science B.V. All rights reserved.