ETCHING OF ZINC SELENIDE AND ZINC TELLURIDE EPITAXIAL-FILMS IN A SECONDARY AFTERGLOW PLASMA - A STATISTICAL EXPERIMENTAL-DESIGN STUDY

The conventional plasma etch processes are not suitable for II-VI compounds. This study describes the systematic development of a novel process for plasma etching of the II-VI compounds ZnSe and ZnTe with CH4/H-2 mixtures in a secondary afterglow plasma using the response surface methodology. The etching process was optimized for obtaining submicrometer structures using thin photomasks that have been exposed to a blue holographic lithography process. Under optimum conditions the etching of such structures without optical (and probably also electrical) degradation is possible with etch rates for ZnSe in the order of 50 nm/min.