Long-Wavelength Ge sub x Si sub l-x/Si Heterojunction Infrared Detectors and Focal Plane Arrays. (Reannouncement with New Availability Information).

摘要

Heterojunction Ge(x)Si(1-x)/Si internal-photoemission infrared detectors exhibiting nearly ideal thermionic-emission dark-current characteristics have been fabricated with cutoff wavelengths out to 25 micrometers. Heteroepitaxial p-Ge(x)i(1-x) layers, degenerately doped with boron to concentrations exceeding 10(20) cm-3 in order to obtain high free-carrier absorption, are grown on Si substrates by molecular beam epitaxy. The detector cutoff wavelength, which is determined to first order by the valence-band offset, is tailored by varying the composition of the Ge(x)Si(1-x) layer and can be fine tuned by adjusting such parameters as the doping concentration and growth temperature. High-quality imaging without uniformity correction has been demonstrated in the long-wavelength infrared spectral band for 400 x 400- and 320 x 244-element focal plane arrays consisting of Ge(x)Si(1-x)/Si detectors, which have cutoff wavelengths of 9.3 and 10.5 micrometers, respectively, and monolithic CCD readout circuitry.