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

J. Schuster; R. E. DeWames; E. A. DeCuir Jr.; E. Bellotti; N. Dhar; P. S. Wijewarnasuriya

doi:10.1117/12.2186043

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28 August 2015 Heterojunction depth in P⁺-on-n eSWIR HgCdTe infrared detectors: generation-recombination suppression

J. Schuster, R. E. DeWames, E. A. DeCuir Jr., E. Bellotti, N. Dhar, P. S. Wijewarnasuriya

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Proceedings Volume 9609, Infrared Sensors, Devices, and Applications V; 960904 (2015) https://doi.org/10.1117/12.2186043
Event: SPIE Optical Engineering + Applications, 2015, San Diego, California, United States

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.

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J. Schuster, R. E. DeWames, E. A. DeCuir Jr., E. Bellotti, N. Dhar, and P. S. Wijewarnasuriya "Heterojunction depth in P⁺-on-n eSWIR HgCdTe infrared detectors: generation-recombination suppression", Proc. SPIE 9609, Infrared Sensors, Devices, and Applications V, 960904 (28 August 2015); https://doi.org/10.1117/12.2186043

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