Variable area MWIR diodes on HgCdTe/Si grown by molecular beam epitaxy

Molecular beam epitaxy technique has been used to grow double layer heteros tructure mercury cadmium telluride materials on silicon substrates for infr ared detection in the mid-wavelength infrared transmission band. Test struc tures containing square diodes with variable areas from 5.76 x 10(-6) cm(2) to 2.5 x 10(-3) cm(2) are fabricated on them. The p on n planar architectu re is achieved by selective arsenic ion implantation. The absorber layer ch aracteristics for the samples studied here include a full width at half max imum of 100-120 arcsec from x-ray rocking curve, the electron concentration of 1-2 x 10(15) cm(-3) and mobility 3-5 x 10(4) cm(2)/V-s, respectively at 80 K from Hall measurements. The minority carrier lifetime measured by pho toconductive decay measurements at 80 K varied from 1 to 1.2 mu sec. A modi fied general model for the variable area I-V analysis is presented. The dar k current-voltage measurements were carried out at 80 K and an analysis of the dependence of zero-bias impedance on the perimeter/area ratio based on bulk, surface generation-recombination, and lateral currents are presented. The results indicate state-of-the art performance of the diodes in the mid wavelength infrared region.