MBE growth of HgCdTe on silicon substrates for large format MWIR focal plane arrays

HgCdTe p-on-n double layer heterojunctions (DLHJs) for mid-wave infrared (M WIR) detector applications have been grown on 100 mm (4 inch) diameter (211 ) silicon substrates by molecular beam epitaxy (MBE). The structural qualit y of these films is excellent, as demonstrated by x-ray rocking curves with full widths at half maximum (FWHMs) of 80-100 arcsec, :Ind etch pit densit ies from 1 x 10(6) to 7 x 10(6) cm(-2). Morphological defect densities for these layers are generally less than 1000 cm(-2). Improving Hg flux coverag e of the wafer during growth can reduce void defects near the edges of the wafers. Improved tellurium source designs have resulted in better temporal flux stability and a reduction of the center to edge x-value variation from 9% to only 2%, Photovoltaic MWIR detectors have been fabricated from some of these 100 mm wafers, and the devices show performance at 140 K which is comparable to other MWIR detectors grown on bulk CdZnTe substrates by MBE a nd by liquid phase epitaxy.