Analysis of adsorption of alcohol additives in the process of silicon etching in alkaline solutions

Abstract

The effect of alcohol additives on silicon anisotropic etching process in KOH solutions has been analysed. It has been stated that the additives modify the anisotropy of the etching process, which results in reduction of etch rates of some crystal planes with specific configuration of surfacial bonds. After considering the bonds configuration on these planes and alcohol molecules dimensions it has been stated that the effective blocking of these planes is directly related to their spatial structure and the structure of alcohol molecule. Obtained results should enable deliberate selection of the additives to etching solutions and the choice of solutions compositions, assuring possible small undercut of convex corners.