ROIC glow reduction in very low flux short wave infra-red focal plane arrays for astronomy

Goff, T. Le; Baier, N.; Gravrand, O.; Nicolas, Jean-Alain; Pichon, Thibault; Boulade, O.

doi:10.1117/12.2560344

Cited by 3 publications

(5 citation statements)

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“…Other strategies are part of detector operation optimization. Output amplifier might remain unused (the so‐called unbuffered mode in HxRG detector), or their biasing can also be tuned to reduce the ROIC contribution to the measured dark signal Le Goff et al (2020).…”

Section: Glow In Infrared Detector Arraysmentioning

confidence: 99%

Pixel source follower glow in HxRG detector

Pichon

Boucher

2023

Astron Nachr

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The Atmospheric Remote‐Sensing Infrared Exoplanet Large‐survey (ARIEL) space mission is dedicated to the study of the exoplanets' atmosphere. To do so, the payload module is made of two instruments. The ARIEL InfraRed Spectrometer instruments is one them, it will perform spectroscopic measurements from the near‐infrared domain to the long‐wave infrared domain. The instrument relies on the use of two H1RG detectors. During early phases of instrument development dark current measurements have been done on an 8 m cutoff detector operated in window mode. These measurements revealed an unexpected level of dark current. This observation triggered a joint series of tests at the European Space Agency technical center and at the Astrophysics Department of the Atomic Energy Commission. As demonstrated in this paper, the excess of dark current originates from the collection, by the photosenstive layer, of light emitted by the source follower transistor of the pixel unit cell. This effect is referred as glow. Based on experimental results, this glow is studied as a function of the detector operating conditions (temperature, biases, timing diagram). These results also show that for the range of operating temperatures considered, the dark current performance of the detector is limited by the glow.

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Section: Glow In Infrared Detector Arraysmentioning

confidence: 99%

Pixel source follower glow in HxRG detector

Pichon

Boucher

2023

Astron Nachr

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“…It is caused by photon emission from a MOSFET in the readout circuit at the boundary of a sensor. 1,2 It can be hard to be ignored and can become prominent in low illumination conditions, particularly in astronomical observations. Sparse sampling readout pattern is used to separate the multiplexer glow in the image sensor of the most powerful space science telescope, the James Webb Space Telescope.…”

Section: Introductionmentioning

confidence: 99%

“…Glow, also known as amplifier glow or amp glow, is not solely related to the self-illumination of an amplifier. It is caused by photon emission from a MOSFET in the readout circuit at the boundary of a sensor 1 , 2 . It can be hard to be ignored and can become prominent in low illumination conditions, particularly in astronomical observations.…”

Section: Introductionmentioning

confidence: 99%

Glow and hot pixels removal using improved robust principal component analysis

Zhang

Liu

et al. 2023

J. Electron. Imag.

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In low-light-level detection, glow and hot pixels in some imaging sensors become visible due to long-exposure time, leading to image quality degradation. To solve the problem of glow and hot pixels in a single image, an improved extraction algorithm based on the idea of robust principal component analysis is proposed to remove them. The image is divided into three terms in our algorithm: a low-rank matrix (image without glow and hot pixels), an extremely sparse matrix (hot pixels), and a sparse and spatially smooth matrix (glow). Specifically, the total variation norm and l 1 -norm are exploited to describe the property of glow. Moreover, a top-hat filter and a boundary-searching method are introduced into the soft threshold operator to improve accuracy. The superiority of the proposed approach is demonstrated with evaluations on simulated datasets, quantitative metrics, and real data.

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Section: -Introductionmentioning

confidence: 99%

“…Moreover, attention should be paid to low light level luminescence emission as these detectors are very sensitive. Typical dark current measured on these detectors are around 0.01 e-/s/pixel [12].Hence, we have performed luminescence measurements at different temperatures ranging from 4 K to 300 K, in order to get insight into the recombination processes involved. This gives us the energy of the photons emitted by spontaneous emission inside the substrate under irradiation.…”

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confidence: 99%

Luminescence Properties of CdTe and CdZnTe Materials When Used as Substrate for IR Detectors

Pichon

Mouzali

Boulade

et al. 2023

J. Electron. Mater.

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I -IntroductionCd1-xZnxTe is a ternary alloy composed of atoms from columns II and VI of the periodic table. The amount of zinc can be tuned depending on the targeted applications, and the electrical properties vary as the amount of zinc is modified. Its high Z number and its high density make the Cd1-xZnxTe semiconductor a suited material for high-performance X-ray and gamma ray detectors for astrophysical and medical applications [1]. Moreover, the CdTe material is widely used in solar cells thanks to its high absorption coefficient in the visible domain [2]. The Cd1-xZnxTe is also used as a substrate material in the fabrication process of infrared (IR) detectors based on HgCdTe technology. The amount of zinc in the alloy is tuned to match the lattice parameter of the epitaxial layer of HgCdTe reducing interfacial defects which may degrade the performance of IR detectors. Generally, the amount of zinc in the alloy when used as substrate for HgCdTe-based IR detectors is approximately equal to 4 % [3].Indeed, the state-of-the-art IR detectors use CdZnTe material as substrate. These IR detectors may then be embarked inside the instruments of satellites. However, space is a harsh environment. In orbit, the satellite and its instruments are impacted by energetic ions (mainly protons) coming from the sun or galactic cosmic rays. Proton irradiation test campaigns on IR detectors have shown an unexpected increase of the detector background under irradiation [4]- [6]. Bright diffuse spots around the protons impact were observed. This pollution of the detector image under irradiation was suspected to be linked to energy deposition inside the Cd1-xZnxTe substrate, where the carriers excited by the passage of the proton inside the substrate lose their energy by emitting photons which are in turn detected by the HgCdTe layer. Thus, a parasitic photonic signal adds up to the useful photonic signal and degrade the detector's sensitivity.It has been shown, that a complete removal of the substrate solves radically the problem [7]-[9], but it constitutes a costy step in the fabrication process. Other published results stated that partially-removed-substrate detectors do not show any increase in the measured background when submitted to proton irradiation [10]. The underlying physical phenomena responsible for the image pollution under irradiation is not fully understood. In our previous work, we adopted a modelling approach in order better understand the latter phenomena and estimate the effect of luminescence in the CdZnTe substrate on the response of IR HgCdTe-based detectors under irradiation [11]. In this model, the optical parameters of CdZnTe material are crucial (particularly the absorption coefficient and energy of the photon emitted by spontaneous emission). In astrophysics, IR detectors are operated at low temperatures (typically 100 K in the short-wave IR domain) to reduce the dark current and increase the sensitivity. Up to our knowledge, not all necessary data are available at these operating temperatures for CdZnTe...

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ROIC glow reduction in very low flux short wave infra-red focal plane arrays for astronomy

Cited by 3 publications

References 0 publications

Pixel source follower glow in HxRG detector

Pixel source follower glow in HxRG detector

Glow and hot pixels removal using improved robust principal component analysis

Luminescence Properties of CdTe and CdZnTe Materials When Used as Substrate for IR Detectors

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