Roughening of single-crystal silicon surface etched by KOH water solution

We investigated roughening of single-crystal silicon surface during chemica l anisotropic etching using KOH water solution. The change in roughness str ongly depends on the crystallographic orientation of the silicon. We plotte d a map showing roughness distribution as a function of orientation. A smoo th surface appears in a region including the (100), (211), and (311) planes . A very rough surface appears in a region including the (320) and (210) pl anes. It was observed that the roughened surface shows facet textures compo sed of certain crystallographic planes. We further studied the effects of K OH concentration and etching temperature. The roughness of (110) plane decr eases with an increase in KOH concentration and is independent of the etchi ng temperature. (C) 1999 Elsevier Science S.A. All rights reserved.