Direct MOVPE growth of HgCdTe on Si substrates for long-wavelength infrared photodiodes

Antiphase- and twinning-free (111)B HgCdTe layers were directly grown on (100) Si substrates by metalorganic vapor phase epitaxy (MOVPE). The quality of the HgCdTe layers was evaluated for long-wavelength infrared (LWIR) photodiodes. Direct growth of (111)B CdTe on (100) Si tended to contain antiphase and twinning due to a lack of polarity in the Si crystal structure. To polarize the nonpolar Si surface, we adsorbed polar molecules on Si surface with metalorganic tellurium (Te). A metalorganic tellurium adsorption and annealing technique is effective for growing high quality CdTe buffer layers on Si substrates. This technique eliminates antiphase domains and prevents twinning. The crystallinity of the Hg 1-x Cd x Te (x equals 0.22 to 0.24) layers grown on Si was evaluated. We have achieved 119 arc sec. full width at half maximum (FWHM) by x-ray analysis and 1.5 multiplied by 10 6 cm -2 etch pit density (EPD) for a 17-micrometer-thick layer. LWIR photodiodes were fabricated from the p-type (111)B HgCdTe layers on (100) Si substrates using planer technology. The n-type regions, formed by boron ion implantation, were 50 micrometer by 75 micrometer by design. A quantum efficiency of 42% was obtained at a cutoff wavelength of 9.0 micrometer at 78 K. The zero bias resistance-area product (R 0 A) was 8.9 multiplied by 10 1 (Omega) cm 2 . We were able to increase the R 0 A and quantum efficiency with MOVPE grown HgCdTe/Si wafers by 50% of those obtained with liquid phase epitaxy (LPE) grown HgCdTe/CdZnTe.