Radiation effects in oxynitrides grown in N/sub 2/O

Saks, N. S.; Simons, M.; Fleetwood, D.M.; Yount, J. T.; Lenahan, P. M.; Klein, Richard B.

doi:10.1109/23.340517

Cited by 24 publications

(9 citation statements)

References 26 publications

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“…The nitridation of the oxide layer enables us to reduce the ionization damage, resulting the effect of the flat-band shift to be smaller than those of devices having only oxides. 9,10) This technique would reduce the dark current for damaged devices. It might not be efficient to improve the CTI since the nitride CCD possesses the similar structure of the depletion layer to the normal CCD.…”

Section: )mentioning

confidence: 99%

Proton Irradiation Experiment for X-ray Charge-Coupled Devices of the Monitor of All-Sky X-ray Image Mission Onboard the International Space Station: I. Experimental Setup and Measurement of the Charge Transfer Inefficiency

Miyata

Kamazuka

Kouno

et al. 2002

Jpn. J. Appl. Phys.

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We have investigated the radiation damage effects on a CCD to be employed in the Japanese X-ray astronomy mission including the Monitor of All-sky X-ray Image (MAXI) onboard the International Space Station (ISS). Since low energy protons release their energy mainly at the charge transfer channel, resulting a decrease of the charge transfer efficiency, we thus focused on the low energy protons in our experiments. A 171 keV to 3.91 MeV proton beam was irradiated to a given device. We measured the degradation of the charge transfer inefficiency (CTI) as a function of incremental fluence. A 292 keV proton beam degraded the CTI most seriously. Taking into account the proton energy dependence of the CTI, we confirmed that the transfer channel has the lowest radiation tolerance. We have also developed the different device architectures to reduce the radiation damage in orbit. Among them, the "notch" CCD, in which the buried channel implant concentration is increased, resulting in a deeper potential well than outside, has three times higher radiation tolerance than that of the normal CCD. We then estimated the charge transfer inefficiency of the CCD in the orbit of ISS, considering the proton energy spectrum. The CTI value is estimated to be 1.1 × 10 −5 per each transfer after two years of mission life in the worse case analysis if the highest radiation-tolerant device is employed. This value is well within the acceptable limit and we have confirmed the high radiation-tolerance of CCDs for the MAXI mission.

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Section: )mentioning

confidence: 99%

Proton Irradiation Experiment for X-ray Charge-Coupled Devices of the Monitor of All-Sky X-ray Image Mission Onboard the International Space Station: I. Experimental Setup and Measurement of the Charge Transfer Inefficiency

Miyata

Kamazuka

Kouno

et al. 2002

Jpn. J. Appl. Phys.

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show abstract

“…It enables us to reduce the ionization damage, resulting the effect of the flat-band shift to be smaller than those of devices having only Si oxides. 14,15 This technique would reduce the dark current for damaged devices whereas it might not be efficient to improve the CTI. However, the degradation of the CTI must be similar level for normal devices.…”

Section: Cti Degradation For Devices Fabricated From Various Wafermentioning

confidence: 98%

Radiation damage test of the x-ray CCDs for MAXI onboard the International Space Station

et al. 2003

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We have investigated the radiation damage effects on a CCD to be employed in the Japanese X-ray astronomy mission including the Monitor of All-sky X-ray Image (MAXI) onboard the International Space Station (ISS). The X-ray CCD camera, ACIS, onboard Chandra have been seriously damaged by low energy protons having energy of ∼150 keV since low energy protons release their energy mainly at the charge transfer channel, resulting a decrease of the charge transfer efficiency. We thus focused on the low energy protons in our experiments. A 171 keV to 3.91 MeV proton beam was irradiated to a given device. We measured the degradation of the charge transfer inefficiency (CTI) and dark current as a function of incremental fluence. A 292 keV proton beam degraded the CTI most seriously. Taking into account the proton energy dependence of the CTI, we confirmed that the transfer channel has a lowest radiation tolerance. On the other hand, dark current increased after proton irradiation for all energies except 171 keV. We have also developed the different device architectures to reduce the radiation damage in orbit. We then investigated the spatial distribution of the low energy protons in the orbit of the ISS. We found that their density has a peak around l ∼ 20 • and b ∼ −55 • independent of the attitude. The peak value is roughly two orders of magnitude larger than that at the South Atlantic Anomaly. Taking into account the new anomaly and orbit of the ISS, we estimated the charge transfer inefficiency of MAXI CCDs to be 1.1 × 10 −5 per each transfer after two years of mission life in the worse case analysis if the highest radiation-tolerant device is employed. This value is well within the requirement and we have confirmed the high radiation-tolerance of MAXI CCDs.

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“…It enables us to reduce the ionization damage, resulting the effect of the flat-band shift to be smaller than those of devices having only Si oxides. 11,12 This technique would reduce the dark current for damaged devices whereas it might not be efficient to improve the CTI. However, the degradation of the CTI must be similar level for normal devices.…”

Section: Cti Degradation For Devices Fabricated From Various Wafermentioning

confidence: 98%

Radiation damage test of the x-ray CCDs with low energy protons

Miyata

Kouno

Kamazuka

et al. 2003

X-Ray and Gamma-Ray Detectors and Applications IV

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We have investigated the radiation damage effects on a CCD to be employed in the Japanese X-ray astronomy mission including the Monitor of All-sky X-ray Image (MAXI) onboard the International Space Station (ISS). The X-ray CCD camera, ACIS, onboard Chandra have been seriously damaged by low energy protons having energy of ∼150 keV since low energy protons release their energy mainly at the charge transfer channel, resulting a decrease of the charge transfer efficiency. We thus focused on the low energy protons in our experiments. We measured the degradation of the charge transfer efficiency and the dark current as a function of incremental fluence. We have also developed the different device architectures to minimize the radiation damage in orbit. We thus compared the differences of performance after proton irradiation. We then investigated the spatial distribution of the low energy protons in the orbit of the ISS. We found that their density has a peak around l ∼ 20 • and b ∼ −55 • independent of the attitude. The peak value is roughly two orders of magnitude larger than that at the South Atlantic Anomaly. Taking into account the new anomaly and orbit of the ISS, we estimated the charge transfer inefficiency of MAXI CCDs to be 1.1 × 10 −5 per each transfer after two years of mission life in the worse case analysis if the highest radiation-tolerant device is employed. This value is well within the requirement and we have confirmed the high radiation-tolerance of MAXI CCDs.

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Radiation effects in oxynitrides grown in N/sub 2/O

Cited by 24 publications

References 26 publications

Proton Irradiation Experiment for X-ray Charge-Coupled Devices of the Monitor of All-Sky X-ray Image Mission Onboard the International Space Station: I. Experimental Setup and Measurement of the Charge Transfer Inefficiency

Proton Irradiation Experiment for X-ray Charge-Coupled Devices of the Monitor of All-Sky X-ray Image Mission Onboard the International Space Station: I. Experimental Setup and Measurement of the Charge Transfer Inefficiency

Radiation damage test of the x-ray CCDs for MAXI onboard the International Space Station

Radiation damage test of the x-ray CCDs with low energy protons

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