DEFECT ETCHING OF BULK GROWN HG1-XCDXTE IN DIFFERENT SOLUTIONS

Samples for the investigation of microstructure were cut from Hg0.8Cd0.2Te ingots grown by the CRA method (Casting Recrystallization Annealing). The most commonly used etchant for the determination of microstructure has been the Polisar solution [Polisar et al, lzv Vuzov Fiz, 6, 81 (1968)] (12 ml HNO3, 5 ml HCl, 1 ml CH3COOH, 1 ml H2O, 0.02 ml Br2). With this solution in our p-type material the existence of precipitate particles up to a density of 10(12) cm-3 has been found. This is in good agreement with the data in the literature [Anderson et al, J Vac Sci Technol, 21 (1982)]. Comparative investigations of microstructural properties of our Hg0.8Cd0.2Te were performed in a new defect etchant proposed by Hahnert and Schenk [J Crystal Growth, 101, 251 (1990)] [1 vol part conc HF, 1 vol part chromic acid, 1 vol part conc HCl, diluted with (H2O)]. This etchant produces etch pits on all crystallographic orientations of surfaces and improves the revelation of grain boundaries, subgrain boundaries and other defects. In this paper a comparison of surfaces etched in both solutions is reported.