Si-29-nuclear magnetic resonance on the etching products of silicon in potassium hydroxide solutions

We present results of Si-29-nuclear magnetic resonance experiments on a lar ge number of KOH solutions in which silicon has been dissolved. The goal of the experiments is to clarify the chemical composition of concentrated alk aline solutions after etching of silicon. It is confirmed that the initial etching product of wet-chemical etching of silicon in KOH is a silicate mon omer. Increasing the silicon content of the solution gives rise to silicate polymerization products. The often reported aging of etching solutions is due to silica in the etchant. (C) 2000 The Electrochemical Society. S0013-4 651(99)10-074-0. All rights reserved.