Investigation of Phase Segregation in Highly Doped InP by Selective Electrochemical Etching

We demonstrate that selective electrochemical etching is a reliable method for detecting and observing the uneven concentration distribution of impurities in indium phosphide crystals, which accompanies the growth of highly doped crystals using the Czochralski method. Even though selective electrochemical etching, as a method of detecting defects in the crystal lattice, has been discussed many times in the literature, it has not yet been described for indium phosphide. In this work, we investigated etching in compositions of various selective electrolytes for InP of n- and p-type conductivity with different surface orientations. We present in detail the features of detecting the striped inhomogeneity of impurity distribution. The mechanisms and peculiarities of the formation of oxide crystallites on the surface of InP during electrochemical processing are presented, including structures like flower-like and parquet crystallites. The formation of porous surfaces, terraces, tracks, and crystallites is explained from the perspective of the defect-dislocation mechanism.