Molecular beam epitaxial growth and performance of HgCdTe-based simultaneous-mode two-color detectors

Abstract

Molecular beam epitaxy was employed for the growth of HgCdTe-based n-p + -n device structures on (211)B oriented CdZnTe substrates. The device structures were processed as mesa isolated diodes, and operated as back-to-back diodes for the simultaneous detection of two closely spaced sub-bands in the mid-wave infrared spectrum. The devices were characterized by R 0 A values in excess of 5 × 10 5 Ω cm 2 at 78K, at f/2 fov and quantum efficiencies greater than 70% in each band. Infrared imagery from a focal plane array with 128 × 128 pixels was acquired simultaneously from each band at temperatures between 77 to 180K, with no observable degradation in the image quality with increase in temperature.

Infrared detectors: an overview

“…Considerable progress has been recently demonstrated in multispectral HgCdTe detectors employing MBE and MOCVD for the growth of variety devices [54][55][56][57][58][59][60][61]. Also QWIP's technology demonstrates considerably progress in fabrication of multicolour FPAs [40,44,[62][63][64][65][66].…”

Infrared Detectors for the Future

“…Using optimized growth condition for Si(211)B substrates and a CdTe/ZnTe buffer system, epitaxial layers with etch pit density (EPD) in the 10 6 cm −2 range have been obtained. This value of EPD has little effect on both MWIR and LWIR HgCdTe/Si detectors [18,14]. By comparison, HgCdTe epitaxial layers grown by MBE or LPE on bulk CdZnTe have typical EPD values in the 10 4 to mid-10 5 cm −2 range where there is a negligible effect of dislocation density on detector performance.…”

“…Dual band detectors are grown by MBE on lattice matched CdZnTe wafers (see Fig. 7) [18,14,[19][20][21][22]. Recently, Raytheon Vision Systems (RVS) has developed two-colour, large-format infrared FPAs to support the US Army's third generation FLIR systems.…”

New material systems for third generation infrared photodetectors

“…A variation on the original back to back concept was implemented using HgCdTe at Rockwell [112] and Santa Barbara Research Center [113]. Following the successful demonstration of multispectral detectors in LPE-grown HgCdTe devices [113], the MBE and MOCVD techniques have been used for the grown of a variety of multispectral detectors at Raytheon [27,[114][115][116][117], BAE Systems [118], Leti [28,30,[119][120][121], Selex and QinetiQ [29,122,123], DRS, [26,124,125] Teledyne and NVESD [126,127]. For more than a decade a steady progression have been made in a wide variety of pixel size (to as small as 20 µm.…”