Wet chemical etching of PbTe and Pb1–xSnxTe crystal surfaces with bromine-releasing aqueous H2O2–HBr–citric acid solutions

Abstract

We have studied the dynamic chemical polishing of single crystals of PbTe and Pb_1–xSn_xTe solid solutions in H₂O₂–HBr–citric acid bromine-releasing etchants under reproducible hydrodynamic conditions and constructed projections of constant etch rate surfaces using simplex design of experiments. The dissolution of the crystals in the polishing mixtures has been shown to be diffusion-limited. The polished surfaces have been characterized by microstructural analysis, scanning electron microscopy, and atomic force microscopy. We have determined the compositions of H₂O₂–HBr–citric acid polishing etchants that can be used for high-quality polishing of the surface of the PbTe and Pb_1–xSn_xTe semiconductor materials at dissolution rates in the range 3.0–18.0 μm/min.