Radiation-induced charge collection in infrared detector arrays

Space Telescope Science Institute, Baltimore, Maryland, United States
IEEE Transactions on Nuclear Science (Impact Factor: 1.28). 01/2003; 49(6):2822 - 2829. DOI: 10.1109/TNS.2002.805382
Source: IEEE Xplore


A modeling approach is described for predicting charge collection in space-based infrared detector arrays due to ionizing particle radiation. The modeling uses a combination of analytical and Monte Carlo techniques to capture the essential features of energetic ion-induced charge collection to detector pixels in a two-dimensional array. The model addresses several aspects that are necessary for high-fidelity simulation of complex focal plane array structures including multiple layers, subregions within layers, variation of linear energy transfer with range, secondary electron scattering, free-field diffusion, and field-assisted diffusion. Example results are given and predictions are compared to experimental data.

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Available from: Bernard Rauscher, Jun 02, 2014
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    • "This work does not address induced radioactivity, which will be different in space than on Earth, due to the different flux, energy, and type of particles in space. Pickel et al. (2002) and Labury (2002) discuss additional modes of ionization in HgCdTe detectors. Also, Groom (2004) reports that stainless steel plates that were exposed to two round trips across the USA on a stratospheric airplane exhibited cosmogenic isotopes that were not present prior to the trip. "
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    ABSTRACT: We hypothesize that the "snowballs" observed in HgCdTe infrared detectors are caused by natural radioactivity in the devices themselves. As characterized by Hilbert (2009) in the WFC3 flight IR array (FPA165), "snowballs" are transient events that instantaneously saturate a few pixels and deposit a few hundred thousand electrons over a ~5-pixel (~100-um) diameter region. In 2008, prior to flight of detector FPA165, Hilbert (2009) detected 21 snowballs during thermal vaccum test three (TV3) and inferred a rate of ~1100 ± 200 snowballs per year per cm2 of the HgCdTe detector. Alpha particles emitted from either (or both) naturally radioactive thorium and/or uranium, at ~1 ppm concentrations within the device, can explain the observed characteristics of the "snowballs." If thorium is present, up to four distinctly observable snowballs should appear at the same location on the pixel array over the course of many years. While the indium in the bump bonds is almost entirely the radioactive isotope In-115, and 12% of the cadmium is naturally radioactive Cd-113, both of those emit only betas, which are too penetrating and not energetic enough to match the observed characteristics of "snowballs." Also, the Cd-113 emission rate is much less than that of the observed snowballs.
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    • "We also present a new first-order model of the charge collection processes in deep trench isolated SiGe HBT devices (this development was motivated by the failure of existing physical models). This model is an extension of the model we presented in [11] for modeling charge collection processes in imagers. The intent of this modeling is to eventually develop an improved on-orbit SEU rate prediction method for IBM SiGe HBT tech- nology. "
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    ABSTRACT: Combining broad-beam circuit level single-event upset (SEU) response with heavy ion microprobe charge collection measurements on single silicon-germanium heterojunction bipolar transistors improves understanding of the charge collection mechanisms responsible for SEU response of digital SiGe HBT technology. This new understanding of the SEU mechanisms shows that the right rectangular parallel-piped model for the sensitive volume is not applicable to this technology. A new first-order physical model is proposed and calibrated with moderate success.
    Full-text · Article · Jan 2004 · IEEE Transactions on Nuclear Science
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    • "Techniques and tools to analyze particle-induced transient effects have been described in [3, 4, and references therein]. Reference [4] also compares modeled results to measured transient response in two scenarios. One comparison is based on flight data for a HgCdTe array exposed to trapped protons, and the other is for a Si visible imaging array exposed to heavy ions under controlled laboratory conditions. "
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    ABSTRACT: We compare measurements and modeling of 27 and 63 MeV proton-induced transients in a large-format HgCdTe long wavelength infrared (LWIR) focal plane assembly operating at 40 K. Charge collection measurements describe very limited diffusion of carriers to multiple pixels showing significantly reduced particle induced cross-talk for the lateral diffusion structure.
    Preview · Article · Jan 2004 · IEEE Transactions on Nuclear Science
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