Surface roughness of single-crystal silicon etched by TMAH solution

We investigated the surface roughness properties of single-crystal silicon etched by a TMAH water solution. We used a hemispherical specimen, in which all crystallographic orientation planes appeared on the surface, and made a map of the surface roughness distribution pattern. The surface roughening and morphology strongly depends on crystallographic orientation. Different types of facet structures appeared at different orientations. The (1 0 0) orientation had the smoothest etched surface. We further studied roughening characteristics, such as dependence on the etching time and TMAH concentration, for the (1 0 0), (1 1 0), and (1 1 1) planes. The roughness values of these three planes depend on the etching time. The values for the (1 0 0) and (1 1 l)planes became saturated as the etching time increased at high TMAH concentration. The roughness of the (1 1 1) surface did not depend on the TMAH concentration, (C) 2001 Elsevier Science B.V. All rights reserved.