OPTIMIZATION OF ETCHANT K2CR2O7 – HBR – LACTIC ACID FOR REMOVING THIN LAYERS FROM THE SURFACE OF CDTE AND ZNXCD1-XTE
DOI:
https://doi.org/10.32782/naturaljournal.11.2025.39Keywords:
chemical dissolution, solid solutions, cadmium telluride, single crystals, etchant, dissolution rate, chemical-dynamic polishingAbstract
In the work, the regularities of chemical-dynamic polishing of the surface of CdTe single crystalsand ZnxCd1-xTe solid solutions (x = 0.04 and 0.1) in aqueous solutions of the system K2Cr2O7 – HBr – lactic acid were investigated. For the first time, the kinetic regularities of the dissolution processof semiconductor surfaces in these solutions were revealed under reproducible hydrodynamic conditions using the rotating disk method. The diagrams “solution composition – polishing rate” of single crystals in the etching compositions of the system K2Cr2O7 – HBr – lactic acid were constructed using the method of mathematical planning of the experiment on a simplex based on the research results, and the concentration limits of polishing and non-polishing solutions were established.The influence of lactic acid and the nature of semiconductors on the dissolution regularities and state of polished surface of CdTe, Zn0.04Cd0.96Te, and Zn0.1Cd0.9Te was determined. It was found that during the polishing of ZnxCd1-xTe solid solutions using the developed etching compositions, an increase inZn content in the semiconductor leads to higher dissolution rates, broader polishing area boundaries, and improved polished surface quality.Kinetic studies confirmed that the physicochemical interaction of semiconductors with polishing etchants is diffusion-limited. It was revealed that the developed etching compositions retain their polishing effect over an extended period (up to 10 days), with only a slight decrease in the polishing rate.A series of new slow polishing etchants was created, optimal parameters of CDP process were developed, and an effective method for washing polished samples after different processing stages was proposed. The surface condition of the samples after treatment was investigated by metallographic, profilometric analyses and atomic force microscopy. It was demonstrated that polishing with the developed etching solutions contributes to the formation of super-smooth (Ra ≤ 10 nm) surface for CdTe single crystals and ZnxCd1-xTe solid solutions.
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