Variable-fluence electrical and transmission electron microscopy studies of defects formed in arsenic-implanted HgCdTe

Arsenic implantation with ion energy 190 keV and fluences 10¹², 10¹³, and 10¹⁴ cm⁻² was performed into a molecular beam epitaxy-grown p–Hg_1-хCd_хTe (х = 0.22) film. The implanted samples were studied with electrical measurements and transmission electron microscopy. The implantation-damaged layers in all the samples appeared to be quite similar and consisted of four sub-layers. These included: a sub-surface layer with low defect density, a deeper layer with big dislocation loops, a yet deeper layer with smaller loops, and a layer with point defects. The characteristic sizes of the first three sub-layers and the density of the defects in them were found to depend on the ion fluence. The results of microstructural studies were compared to those of the Hall-effect measurements processed with discrete mobility spectrum analysis. The fluence dependence of both the carrier concentration and the depth of the p–n junction was established.