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Proceedings Paper

Heterojunction depth in P+-on-n eSWIR HgCdTe infrared detectors: generation-recombination suppression
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Paper Abstract

A key design feature of P+-on-n HgCdTe detectors is the depth of the p-type region. Normally, homojunction architectures are utilized where the p-type region extends into the narrow-gap absorber layer. This facilitates the collection of photo-carriers from the absorber layer to the contact; however, this may result in excess generation-recombination (G-R) current if defects are present. Alternatively, properly adopting a heterojunction architecture confines the p-type region (and the majority of the electric field) solely to the wide-gap layer. Junction placement is critical since the detector performance is now dependent on the following sensitivity parameters: p-type region depth, doping, valence band offset, lifetime and detector bias. Understanding the parameter dependence near the hetero-metallurgical interface where the compositional grading occurs and the doping is varied as either a Gaussian or error function is vital to device design. Numerical modeling is now essential to properly engineer the electric field in the device to suppress G-R current while accounting for the aforementioned sensitivity parameters. The simulations reveal that through proper device design the p-type region can be confined to the wide-gap layer, reducing G-R related dark current, without significantly reducing the quantum efficiency at the operating bias V = -0.100V.

Paper Details

Date Published: 28 August 2015
PDF: 12 pages
Proc. SPIE 9609, Infrared Sensors, Devices, and Applications V, 960904 (28 August 2015); doi: 10.1117/12.2186043
Show Author Affiliations
J. Schuster, U.S. Army Research Lab. (United States)
Boston Univ. (United States)
R. E. DeWames, Fulcrum Co. (United States)
E. A. DeCuir, U.S. Army Research Lab. (United States)
E. Bellotti, Boston Univ. (United States)
N. Dhar, U.S. Night Vision Electronic Sensing Directorate (United States)
P. S. Wijewarnasuriya, U.S. Army Research Lab. (United States)


Published in SPIE Proceedings Vol. 9609:
Infrared Sensors, Devices, and Applications V
Paul D. LeVan; Ashok K. Sood; Priyalal Wijewarnasuriya; Arvind I. D'Souza, Editor(s)

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