Research
at Microphysics Lab

Variable area MWIR Diodes on HgCdTe/Si grown by Molecular Beam Epitaxy


Research Note:

Test structures containing mini arrays of square diodes with variable area from 5.76x10^-6 cm^-2 to 2.5x10^-3 cm^-2 were fabricated on heterostructure mercury cadmium telluride layers grown on silicon substrates by molecular beam epitaxy. The p on n planar architecture is achieved by selective arsenic ion implantation. Results of x-ray diffraction (full width at half maximum (FWHM) = 120 arc sec), Hall (electron concentration and mobility in the absorber layer, 1x10¹⁵ cm^-3 and 5x10⁴ cm²/V-s), and photoconductive lifetime measurements at 80 K (hole lifetime in the absorber layer = 1.18 msec) have been already reported. Current-voltage measurement results at 80 K and an analysis of the dependence of zero-bias impedance on perimeter/area ratio based on bulk diffusion, bulk generation-recombination(g-r), lateral currents and surface g-r currents have also been reported. The results indicate state-of-the art performance of the diodes in midwavelength infrared region.