Etching Behavior of CdTe, CdTe, CdTe, and CdTe Single Crystals in Aqueous (NH_4)_2Cr_2O_7-HBr-Citric Acid Solutions

摘要

We have studied the dissolution behavior of undoped and Group IV (Ge, Sn, and Pb) doped cadmium telluride single crystals in aqueous (NH_4)_2Cr_2O_7-HBr-citric acid solutions, constructed dissolution rate-etchant composition diagrams, and located the composition regions of polishing, selective, and nonpolishing solutions. The doping effect on the chemical etching process has been examined, and the rate-limiting steps in the chemical dissolution of the materials studied have been identified. We have assessed the surface condition of the etched crystals by microstructural analysis and surface profilometry and optimized the etchant composition for the dynamic chemical polishing of these semiconductors.