Ion milling was used to establish the minimum donor doping level N md required for obtaining n-regions with reproducible electron concentration in HgCdTe-based LWIR and MWIR device structures fabricated with ion treatment. The experiments were performed on n-type films grown by molecular beam epitaxy, un-doped and in situ doped with indium with the concentration N In = 5 × 10 14 -10 17 cm −3 . A study of the electrical properties of the milled films showed that N md comprised ∼2 × 10 15 cm −3 for the LWIR and ∼5 × 10 15 cm −3 for the MWIR films. In the films with N In exceeding these critical values, the electron concentration after the milling strictly followed the doping. A need for consideration of the disintegration of the milling-induced defects is also shown.

The relaxation of electrical properties of As-and Sb-doped HgCdTe epitaxial layers, which were converted into n-type by ion milling, is studied. It is shown that donor complexes formed under ion milling and responsible for p-to-n conductivity type conversion are not stable, and their concentration decreases upon storage even at room temperature. Increasing the temperature of the storage speeds up the relaxation process. It is demonstrated that the relaxation is caused by the disintegration of the donor complexes that starts right after the end of the milling process because of the decrease in the concentration of interstitial mercury atoms, which were generated during the milling. The results presented in the paper are important for the development of the technology of photodetectors based on HgCdTe doped with V-group acceptors.

The effect of ion milling on electrical properties of vacancy-and arsenic-doped p-Hg 1−x Cd x Te (MCT) (x ∼ 0.22) has been studied. Samples for the study were fabricated by thermal annealing of n-type heterostructures grown by molecular beam epitaxy (MBE) on GaAs. Their behaviour under ion milling was compared to that of MCT bulk samples and films grown by liquid and vapour phase epitaxy. Residual donor concentration in the MBE-grown structures was found to be of the order of 10 15 cm −3 , which is typical for MCT. Unique to the MBE structures was high electron concentration (∼10 17 cm −3 ) straight after the milling. We suppose that this fact reflected ion-milling-induced activation of an initially neutral defect, which was formed in the heterostructures during the growth. A possible nature of the defect is discussed.