Improving radiation tolerance in e2v CCD sensors

Burt, David; Endicott, J.; Jerram, Paul; Pool, P.; Morris, D.; Hussain, Aqil; Ezra, P.

doi:10.1117/12.825273

Cited by 17 publications

(20 citation statements)

References 3 publications

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“…Dopant Region P P P P P P P P P P P P P P P P P P Phosphorus dopant atoms Figure 2. Radiation damage mechanism for a high energy proton in a CCD (adapted from [7]). …”

Section: Radiation Damage and Charge Transfer Inefficiency (Cti)mentioning

confidence: 99%

Modelling charge transfer in a radiation damaged charge coupled device for Euclid

Hall

Holland

Murray

et al. 2012

High Energy, Optical, and Infrared Detectors for Astronomy V

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As electrons are transferred through a radiation damaged Charge Coupled Device (CCD), they may encounter traps in the silicon in which they will be captured and subsequently released. This capture and release of electrons can lead to a 'smearing' of the image. The dynamics of the trapping process can be described through the use of Shockley-Read-Hall theory, in which exponential time constants are used to determine the probability of capture and release. If subjected to a hostile radiation environment, such as in space where the dominant charged particle is the proton, these incident protons can cause displacement damage within the CCD and lead to the formation of stable trap sites. As the trap density increases, the trapping and release of signal electrons can have a major impact on the Charge Transfer Efficiency (CTE) to the detriment of device performance. As the science goals for missions become ever more demanding, such as those for the ESA Euclid and Gaia missions, the problem of radiation damage must be overcome. In order to gain a deeper understanding of the trapping process and the impact on device performance, a Monte Carlo simulation has been developed to model the transfer of charge in a radiation damaged CCD. This study investigates the various difficulties encountered when developing such a model: the incorporation of appropriate clocking mechanisms, the use of suitable trap parameters and their degeneracy, and the development of methods to model the charge storage geometry within a pixel through the use of three-dimensional Silvaco simulations.

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“…Dopant Region P P P P P P P P P P P P P P P P P P Phosphorus dopant atoms Figure 2. Radiation damage mechanism for a high energy proton in a CCD (adapted from [7]). …”

Section: Radiation Damage and Charge Transfer Inefficiency (Cti)mentioning

confidence: 99%

Modelling charge transfer in a radiation damaged charge coupled device for Euclid

Hall

Holland

Murray

et al. 2012

High Energy, Optical, and Infrared Detectors for Astronomy V

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“…Our original interpretation 26 of the cause was because of the formation of trapped holes in the oxide being compensated by electrons trapped in the Si3N4 (of the Si3N4-SiO2 gate dielectric), thereby resulting in a lower flatband shift described by Saks et al 1979 27 . However, this original interpretation was incorrect because e2v n-channel CCDs also benefit from this process 25 .…”

Section: Resultsmentioning

confidence: 99%

“…The onset of blooming occurs around 300 rows earlier than in the control region, and indicates a decrease in the SatLin of around 50k holes. The reduction in full well is likely to be the resulting flatband voltage which occurs during the irradiation, in e2v n-channel CCDs this is typically 100-200 mV per krad 13 for a standard gate CCD (for example the p-channel and n-channel CCD204) 25 . The total ionising dose (TID) delivered during the irradiation was 65 krad.…”

Section: Resultsmentioning

confidence: 99%

Postirradiation behavior of p-channel charge-coupled devices irradiated at 153 K

Gow

Wood

Murray

et al. 2016

J. Astron. Telesc. Instrum. Syst

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b e2v technologies plc, 106 Waterhouse Lane, Chelmsford, Essex, CM1 2QU, UK.Abstract. The displacement damage hardness that can be achieved using p-channel charge coupled devices (CCD) was originally demonstrated in 1997, and since then a number of other studies have demonstrated an improved tolerance to radiation-induced CTI when compared to n-channel CCDs.A number of recent studies have also shown that the temperature history of the device after the irradiation impacts the performance of the detector, linked to the mobility of defects at different temperatures. This study describes the initial results from an e2v technologies p-channel CCD204 irradiated at 153 K with a 10 MeV equivalent proton fluences of 1.24×10 9 and 1.24×10 11 protons.cm -2 . The dark current, cosmetic quality and the number of defects identified using trap pumping immediately were monitored after the irradiation for a period of 150 hours with the device held at 153 K and then after different periods of time at room temperature. The device also exhibited a flatband voltage shift of around 30 mV per krad, determined by the reduction in full well capacity.

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“…Through carefully choosing the device temperature or the way in which the device is operating, it has been shown that the effect of the radiation-induced traps can be reduced dramatically [42,43]. The third method involves the correction of smeared images through post-processing [36,44,45], as shown in Figure 1, making use of models of the charge transfer in the CCD in the presence of traps [44][45][46][47]. This correction is usually required alongside the optimisation of the device design and device operation to reach the level of correction required.…”

Section: Motivationmentioning

confidence: 99%

Vacancy-oxygen defects in silicon: the impact of isovalent doping

Londos

Sgourou

Hall

et al. 2014

J Mater Sci: Mater Electron

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Silicon is the mainstream material for many nanoelectronic and photovoltaic applications. The understanding of oxygen related defects at a fundamental level is essential to further improve devices, as vacancy-oxygen defects can have a negative impact on the properties of silicon. In the present review we mainly focus on the influence of isovalent doping on the properties of A-centers in silicon. Wherever possible, we make comparisons with related materials such as silicon germanium alloys and germanium. Recent advanced density functional theory studies that provide further insights on the charge state of the A-centers and the impact of isovalent doping are also discussed in detail.

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Improving radiation tolerance in e2v CCD sensors

Cited by 17 publications

References 3 publications

Modelling charge transfer in a radiation damaged charge coupled device for Euclid

Modelling charge transfer in a radiation damaged charge coupled device for Euclid

Postirradiation behavior of p-channel charge-coupled devices irradiated at 153 K

Vacancy-oxygen defects in silicon: the impact of isovalent doping

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