Cation impurity gettering in Hg1-xCdxTe was considered in terms of process models which took account of interactions of the impurities with the predominant native point defects. The experimental results were in the form of secondary ion mass spectroscopic profiles of Au redistribution in samples with x-values of 0.2, 0.3, or 0.4, after Hg annealing or ion-milling. The latter processes were known to inject excess Hg interstitials. In the case of both processes, the IB impurity was preferentially distributed to regions of high vacancy concentration. The junction depth of the low-to-high impurity transition was determined by secondary ion mass spectrometry. After Hg-rich annealing of Au-doped high vacancy content material, the impurity junction behavior with respect to annealing time and temperature was compared with that which was expected for type-converted electrical junctions in vacancy-only material. In the case of milled Au-doped Hg0.7Cd0.3Te, with a high vacancy concentration, the impurity junction depths were approximately proportional to the amount of material which was removed, as in the case of material with x = 0.2. The Hg-annealing type-conversion rates were found to exhibit a strong compositional dependence which compared favorably with the strong self-diffusion coefficient dependence upon the x-value. On the other hand, the mill conversion rate exhibited a weak x-value dependence. The effects of trace or predominant Au levels, as compared with the background vacancy concentration, were considered. It was concluded that the true decoration of intrinsic defect processes required that the Au concentration should be much lower than the cation vacancy concentration.

J.L.Meléndez, J.Tregilgas, J.Dodge, C.R.Helms: Journal of Electronic Materials, 1995, 24[9], 1219-24