Journal of Electronic Materials

, Volume 40, Issue 8, pp 1618–1623

Planar n-on-p HgCdTe FPAs for LWIR and VLWIR Applications

  • R. Wollrab
  • A. Bauer
  • H. Bitterlich
  • M. Bruder
  • S. Hanna
  • H. Lutz
  • K.-M. Mahlein
  • T. Schallenberg
  • J. Ziegler
Article

DOI: 10.1007/s11664-011-1659-0

Cite this article as:
Wollrab, R., Bauer, A., Bitterlich, H. et al. Journal of Elec Materi (2011) 40: 1618. doi:10.1007/s11664-011-1659-0

Abstract

Mainly driven by space applications, mercury cadmium telluride (MCT) focal-plane arrays (FPAs) have been successfully developed for very long wavelengths (λCO > 14 μm at 55 K). For this purpose, the standard n-on-p technology based on MCT grown by liquid-phase epitaxy (LPE) and involving vacancy doping has been modified to extrinsic doping by a monovalent acceptor. Due to the planar diode geometry obtained by ion implantation, most of the carrier generation volume is located in the p-type region with a thickness of approximately 8 μm. According to our understanding, the Shockley–Read centers connected with the Hg vacancies are thus significantly reduced. This situation should lead to longer minority-carrier lifetimes and smaller generation rates under equilibrium conditions, therefore yielding lower dark current. We indeed observe a reduction by a factor of approximately 15 by using extrinsic doping. Recent dark current data obtained in the temperature range from 55 K to 85 K on 288 × 384 FPAs with λCO(60 K) = 12 μm, either intrinsically or extrinsically doped, corroborate this finding. These data, new results on a 112 × 112 pixel demonstrator array with λCO(55 K) = 14.4 μm, and earlier measurements are compared with Tennant’s Rule 07 established for p-on-n technology.

Keywords

HgCdTe infrared detector liquid-phase epitaxy (LPE) very long-wavelength infrared (VLWIR) extrinsic doping dark current 

Copyright information

© TMS 2011

Authors and Affiliations

  • R. Wollrab
    • 1
  • A. Bauer
    • 1
  • H. Bitterlich
    • 1
  • M. Bruder
    • 1
  • S. Hanna
    • 1
  • H. Lutz
    • 1
  • K.-M. Mahlein
    • 1
  • T. Schallenberg
    • 1
  • J. Ziegler
    • 1
  1. 1.AIM INFRAROT-MODULE GmbHHeilbronnGermany

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