Fabrication of high-performance large-format MWIR focal plane arrays from MBE-grown HgCdTe on 4 '' silicon substrates

We have developed the capability to grow HgCdTe mid-wave infrared radiation double-layer heterojunctions (MWIR DLHJs) on 4" Si wafers by molecular bea m epitaxy (MBE), and fabricate devices from these wafers that are comparabl e to those produced by mature technologies. Test data show that the detecto rs, which range in cutoff wavelength over 4-7 mum, are comparable to the tr endline performance of liquid phase epitaxy (LPE)-grown material. The spect ral characteristics are similar, with a slight decrease in quantum efficien cy attributable to the Si substrate. With respect to R(0)A, the HgCdTe/Si d evices are closer to the theoretical radiative-limit than LPE-grown detecto rs. Known defect densities in the material have been correlated to device p erformance through a simple model. Slight l/f noise increases were measured in comparison to the LPE material, but the observed levels are not suffici ent to significantly degrade focal plane array (FPA) performance. In additi on to discrete detectors, two FPA formats were fabricated. 128 x 128 FPAs s how MWIR sensitivity comparable to mature InSb technology, with pixel opera bility values in excess of 99%. A 640 x 480 FPA further demonstrates the hi gh-sensitivity and high-operability capabilities of this material.