Anisotropic dissolution of single-crystal silicon near the chemical mask edge on the (001) surface

The features of the micro- and nanorelief of the single-crystal silicon (001) surface formed near the vertex of the convex right corner of 〈110〉- and 〈100〉-oriented edges of a chemical mask during etching in KOH aqueous solutions (8–16 mol/l) at temperatures of 60–80°C were studied using a LEO-1420 scanning electron microscope and a MII-4 microinterferometer. It was found that microfacets formed immediately near the vertex of a convex corner of the mask are not perfect low-index microfaces of the crystal. The dependences of the crystallographic orientation and normal etch rates of such facets on experimental conditions were determined. The dependence of the effective activation energy of dissolution of the studied surfaces on the KOH concentration was estimated.