Evolution and Impact of Defects in a p-Channel CCD After Cryogenic Proton-Irradiation

Wood, Daniel; Hall, D.; Gow, Jason; Skottfelt, J.; Murray, Neil J.; Stefanov, Konstantin D.; Holland, Andrew D.

doi:10.1109/tns.2017.2756019

Cited by 12 publications

(11 citation statements)

References 21 publications

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“…The "single trap pumping" technique allows characterization of individual defects within the transfer channel of the device, providing information on their precise location, emission time constant, energy level, and cross section. [31][32][33][34][35][36][37] A detailed description of the development of the underlying theory can be found within Ref. 18, and Ref.…”

Section: Probing Silicon Defects Within Emccdsmentioning

confidence: 99%

Proton-induced traps in electron multiplying charge-coupled devices

Bush

Hall

Holland

2021

J. Astron. Telesc. Instrum. Syst.

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Charge-coupled device (CCD)-based technologies exposed to high-energy radiation are susceptible to the formation of stable defects within the charge transfer channel that defer signal to subsequent pixels and limit the lifetime of the detector. Performance degradation due to these defects depends upon the interplay between the clock timings used to operate the device and the properties of defects introduced by irradiation. Characterization of both the type and number of post-irradiation defects makes it possible to minimize charge loss though the appropriate selection of clock timings for a given operating temperature. This technique has the potential to increase nominal mission lifetimes by several years for CCD-based instruments and is of particular significance to electron multiplying charge-coupled devices (EMCCDs) for photon counting applications where the effect of charge traps on low signal levels is expected to be most severe. We present a study of charge traps within CCDs, specifically within EMCCDs irradiated at room temperature to proton fluences up to and including 1.45 × 10 10 p þ ∕cm 2 (74 MeV). Defects are characterized through the "single-trap pumping" technique, with clocking schemes specifically designed for the 2-phase pixel architecture of the EMCCD. Five dominant trap species are thought to be introduced by the irradiation, the Si-E center, Si-A center, double and single acceptor charge states of the silicon divacancy (VV −− , VV − ), and an as yet unidentified defect referred to here as the Si-U center (the "unknown" trap). Energy-level and crosssection values are presented that allow inference of the defect landscape for a range of proton fluences and operating temperatures. While the study focuses specifically on EMCCDs, in more general terms, the results for trap properties are interpreted as being applicable to all CCD types following irradiation and can serve as a foundation for future charge loss correction and optimization techniques.

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Section: Probing Silicon Defects Within Emccdsmentioning

confidence: 99%

Proton-induced traps in electron multiplying charge-coupled devices

Bush

Hall

Holland

2021

J. Astron. Telesc. Instrum. Syst.

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“…While methods such as first pixel response and extended pixel edge response 1 are only able to give information about average properties of the traps in the CCD, the trap pumping technique [2][3][4][5][6][7] is able to probe the individual traps. Trap pumping works by clocking charge back and forth among the pixels such that each trap creates a dipole for which the intensity depends on how close the emission time constant is to the clocking time.…”

Section: Introductionmentioning

confidence: 99%

“…While methods such as First Pixel Response (FPR) and Extended Pixel Edge Response (EPER) 1 are only able to give information about average properties of the traps in the CCD, the trap pumping technique [2][3][4][5][6] is able to probe the individual traps. This means that information about the emission time constant, energy level, capture cross section, sub-pixel positions etc.…”

Section: Introductionmentioning

confidence: 99%

Importance of charge capture in interphase regions during readout of charge-coupled devices

Skottfelt¹,

Hall

Dryer

et al. 2018

J. Astron. Telesc. Instrum. Syst.

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Abstract. The current understanding of charge transfer dynamics in charge-coupled devices (CCDs) is that charge is moved so quickly from one phase to the next in a clocking sequence and with a density so low that trapping of charge in the interphase regions is negligible. However, simulation capabilities developed at the Centre for Electronic Imaging, which includes direct input of electron density simulations, have made it possible to investigate this assumption further. As part of the radiation testing campaign of the Euclid CCD273 devices, data have been obtained using the trap pumping method, a method that can be used to identify and characterize single defects within CCDs. Combining these data with simulations, we find that trapping during the transfer of charge among phases is indeed necessary to explain the results of the data analysis. This result could influence not only trap pumping theory and how trap pumping should be performed but also how a radiation-damaged CCD is readout in the most optimal way.

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“…The trap pumping technique [13] [14] [15] [16] [17] [18] [19] allows the emission time constants of the intrinsic and radiation-induced defects within the silicon CCD to be calculated, which can then be collated to provide an overall representation of the spread of emission time constants within the device. The underlying theory is based upon Shockley-Read-Hall recombination statistics [9] [10].…”

Section: Trap Pumpingmentioning

confidence: 99%

Effects of Temperature Anneal Cycling on a Cryogenically Proton Irradiated CCD

Parsons,

Buggey,

Holland

et al. 2021

Preprint

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Throughout a typical Earth orbit a satellite is constantly bombarded by radiation with trapped and solar protons being of particular concern as they gradually damage the focal plane devices throughout the mission and degrade their performance. To understand the impact the damage has on CCDs and how it varies with their thermal history a proton radiation campaign has been carried out using a CCD280. The CCD is irradiated at 153 K and gradually warmed to 188 K in 5 K increments with Fe 55 X-ray, dark current and trap pumping images taken at 153 K after each anneal step.The results show that despite the trap landscape changing throughout the anneal it has little impact on parallel charge transfer inefficiency. This is thought to be because most traps are unaffected and a lot of those that do anneal only move from the continuum between distinct trap species and into a nearby divacancy trap "peak" whose emission time constant is similar enough to still impact the CTI.In terms of using a CCD280 or similar devices in a mission the CTI being unaffected by thermal annealing up to 188 K means that any CTI correction needed as the radiation damage builds up does not have to take into account the thermal history of the focal plane. However, it is possible that a significant amount of annealing will occur at temperatures greater than 188 K and care should be taken when a mission is operating in this range to gather accurate pre-flight data K : CCD, radiation damage, temperature annealing, radiation damage, X-ray detectors, trap pumping, charge transfer inefficiency

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Evolution and Impact of Defects in a p-Channel CCD After Cryogenic Proton-Irradiation

Cited by 12 publications

References 21 publications

Proton-induced traps in electron multiplying charge-coupled devices

Proton-induced traps in electron multiplying charge-coupled devices

Importance of charge capture in interphase regions during readout of charge-coupled devices

Effects of Temperature Anneal Cycling on a Cryogenically Proton Irradiated CCD

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