Theoretical performance of mid wavelength HgCdTe(1 0 0) heterostructure infrared detectors

Abstract

The paper presents a theoretical study of the p+BpnN+ design based on HgCdTe(100) layers, which significantly improves the performance of detectors optimized for the mid-wave infrared spectral range. p+BpnN+ design combines the concept of a high impedance photoconductor with double layer hetero-junction device. Zero valence band offset approximation throughout the p+Bpn heterostructure allows flow of only minority holes generated in the absorber, what in a combination with n-N+ exclusion junction provides the Auger suppression. Modeling shows that by applying a low doping active layer, it is possible to achieve an order of magnitude lower dark current densities than those determined by “Rule 07”. A key to its success is a reduction of Shockley-Read-Hall centers associated with native defects, residual impurities and misfit dislocations. Reduction of metal site vacancies below 1012cm−3 and dislocation density to 105cm−2 allow to achieve a background limited performance at 250K. If the background radiation can be reduced, operation with a three- or four-stage thermo-electric-cooler may be possible.