Malanych G. Interaction of the PbTe and Pb1-xSnxTe solid solutions with H2O2–НBr–solvent etching compositions

Thesis is devoted to the investigation of the interaction of the PbTe and Pb0,83Sn0,17Te, Pb0,8Sn0,2Te (І) and Pb0,8Sn0,2Te (ІІ) solid solutions single crystals with the H2O2–HBr–solvent bromine-emerging mixtures and to the development of the etchant compositions and the schedule of the surface treatment of the mentioned above semiconductor materials using the obtained experimental data. The dissolution nature of these semiconductor materials in the aqueous solutions of the H2O2–HBr–ethylene glycol, H2O2–HBr–acetic, H2O2–HBr– lactic, H2O2–HBr–oxalic, H2O2–HBr–tartaric, H2O2–HBr–citric acid have been investigated and 24 diagrams “etchant composition – etching rate” with determining the regions of polishing and unpolishing solutions have been constructed. The dependences of the etching rates from temperature and disc rotation speed have been determined and it was shown that the dissolution process of mention above semiconductor materials in the H2O2–HBr–solvent polishing solutions is determined by the diffusion stages. Analyzing the temperature dependences of the etching rates it was confirmed the existence of the compensating effect in the kinetics of the PbTe and Pb1-xSnxTe chemical etching by the H2O2–HBr–solvent etchant compositions. The influence of the solvent nature and hydrobromic acid concentration on the chemical dissolution rate, polishing properties of the solutions and quality of the polishing surfaces has been determined. It was shown that the increasing of tin content in the Pb1-xSnxTe solid solution does not change the etching rate and decreases slightly the polishing solution regions. The influence of the quantitative and qualitative etchant compositions and the chemical treatment procedures on the PbTe and Pb1-xSnxTe solid solution surface roughness have been established using metallography, combined light scattering spectroscopy and scanning electron microscopy. The polishing etchant compositions H2O2–HBr–solvent and technological procedures of the chemical-dynamical and chemical-mechanical polishing for the disturbed layer elimination, controlled thinning of the plates up to reference dimension, the thin layers removing and PbTe and Pb1-xSnxTe solid solution finishing polishing have been optimized.