The Chemical Etching of II – VI / GaAs Heterostructures in Aqueous I : KI : HBr Solutions

The etching characteristics of CdTe , HgTe , Hg 0.6 Cd 0.4 Te , and a CdTe / HgTe multilayered structure in aqueous I : KI : HBr solutions have been studied using films grown by metal‐organic chemical vapor deposition on 2° misoriented (100) GaAs . The dissolution rate of the films was found to be linearly dependent on the [ I : KI ] ω / ω ratio of the etchant, indicative of a kinetically controlled process. In terms of the mesa etching of II–VI heterostructures, the optimum range of solution composition was [ I : KI ] ω / ω < 0.25 , allowing the definition of structures with minimum dimensions approaching 1 μm. Quantitative analyses of the etched films by XPS have compared the effects of different [ I : KI ] ω / ω ratios on the formation of nonstoichiometric surface layers.