On the Miller-indices determination of Si{1 0 0}convex corner undercut planes

The Miller-indices determination of the arising surfaces at the Si(0 0 1) convex corner due to anisotropic etching is investigated. We propose a 2D zoning model in which the undercut planes arising at a masked convex corner are presumed to be in the same zone as the sidewalls forming the convex corner, which is characterized by the parallelism of the intersection lines of each pair of new surfaces and the sidewalls. Based on this model a method combining the experimental data, analytical geometry and stereographic projection is presented to systematically determine the Miller indices of the arising planes. The quantitative prediction of undercut planes is confirmed by the angle measurement using a surface profiler.