Stanetska A. Interaction of undoped and doped ZnSe crystals with bromine emerging etching compositions based on H2O2–HBr

The thesis is devoted to the investigation of chemical interaction of undoped and doped ZnSe crystals with bromine emerging solutions of H2O2–HBr–solvent. According to the results of mathematical simulation of the experiments 21 diagrams “etchant composition – etching rate” of these crystals in the solutions of H2O2–HBr–ethylene glycol, H2O2–HBr– Н2О, H2O2–HBr–oxalic and H2O2–HBr–acetic acid with determining of the boundaries regions of polishing and unpolishing solutions have been constructed. The dependences of the dissolution rates on temperature and rotation speed as well as limiting stages of the dissolution process of semiconductors, the influence of doping on the etching rate and the regions of polishing solutions have been determined. The influence of solvent nature and content of H2O2 on the chemical dissolution rate, polishing properties of the solutions and quality of the treated surfaces has been also determined. Analyzing the temperature dependences of the etching rates it was confirmed the existence of the compensating effect in the kinetics of zinc selenide crystals chemical etching by the H2O2–HBr–solvent etchant compositions. The results of electronic, atomic force microscopy and low temperature photoluminescence suggest high quality of polished semiconductors surface. For the first time the etching rate dependence of the chemical polishing on the degree of dilution base polishing solutions H2O2–HBr–organic component of viscous solvents as well as the influence of the their nature and concentration on the polishing properties of the formed etching rate and the condition of polished surface of crystals have been set. The polishing etchant compositions H2O2–HBr–solvent and technological procedures of the chemical-dynamical and chemical-mechanical polishing to remove the damaged layer, controlled thinning of the plates to the specified size, the thin layers removing and finishing polishing of ZnSe, ZnSe(Al) and ZnSe(Te) crystals have been optimized.