The potential dependence of silicon anisotropic etching in KOH at 60°c

Abstract

The electrochemistry and potential dependent etching of silicon in 40% KOH at 60 ° C is investigated. A new technique, which produces an almost perfect (111) silicon crystal face, was used to obtain the true electrochemical characteristics of the (111) crystal plane. From i-V sweep rate dependence, it was discovered that the process of anodic oxide formation on (111) silicon uses a constant quantity of charge, 2.4×10 −3 C cm −2, and that the potential denoted classically as the passivation potential on n-type (100) silicon does not correspond to the potential of anodic oxide formation. The oxide formation potentials determined from i-V behavior are confirmed by oxide etch-back experiments.