Total ionizing dose effect on 2-D array data transfer ICs designed and fabricated by 0.18-µm CMOS technology

Circuits for CMOS two-dimensional (2-D) array data transfer are indispensable for applications such as space and nuclear fields. Issues include to be operated with higher speed, lower power, fewer size penalty and radiation hardness. To meet these requirements, two kinds of CMOS 2-D array data transfer circuits, such as a shift register type and a memory access type, are proposed and fabricated by the standard 0.18-µm CMOS process technology. In the both types, 16 µm pitch, 8×124 array data transfer operations were realized with data rate of more than 1 Gb/s. Furthermore, we conducted 60Co γ-ray irradiation experiments on those circuits. The current consumption ratio of the shift register type to the memory access type ranges from 150 to 200% as the dosage increases. The result indicate that the memory access type has better radiation hardness at 1 Gb/s than that of the shift register type.

Radiation Hardness of 4H-SiC P-N Junction UV Photo-Detector

4H-SiC based p-n junction UV photo-detectors were irradiated with 600 keV He+ in the fluence range of 5 × 1011 ÷ 5 × 1014 ion/cm2 in order to investigate their radiation hardness. The effects of irradiation on the electro-optical performance were monitored in dark condition and in the UV (200 ÷ 400 nm) range, as well as in the visible region confirming the typical visible blindness of unirradiated and irradiated SiC photo-sensors. A decrease of UV optical responsivity occurred after irradiation and two fluence regimes were identified. At low fluence (<1013 ions/cm2), a considerable reduction of optical responsivity (of about 50%) was measured despite the absence of relevant dark current changes. The presence of irradiation induced point defects and then the reduction of photo-generated charge lifetime are responsible for a reduction of the charge collection efficiency and then of the relevant optical response reduction: point defects act as recombination centers for the photo-generated charges, which recombine during the drift/diffusion toward the electrodes. At higher irradiation fluence, the optical responsivity is strongly reduced due to the formation of complex defects. The threshold between low and high fluence is about 100 kGy, confirming the radiation hardness of SiC photo-sensors.

An Energy-Efficient Low-Area Double-Node-Upset-Hardened Latch Design

The energy-efficient circuits, though important in IoT and biomedical applications, are vulnerable to soft errors due to their low voltages and small node capacitances. This paper presents an energy-efficient low-area double-node-upset-hardened latch (EEDHL). The proposed latch enhances the radiation hardness by employing a restorer circuit based on a Muller C-element and a memory element. The post-layout simulations show that the EEDHL improves the area–energy–delay product (AEDP) by [Formula: see text]80% compared to the newly reported double-node-upset-resilient latch (DNURL) in STMicroelectronics 65-nm CMOS technology. Synopsys TCAD mixed-mode simulations in 32-nm CMOS technology framework are also used to validate the proposed DNU-hardened latch. The proposed EEDHL effectively mitigates the DNU at the strike with a linear energy transfer (LET) equal to 160[Formula: see text][Formula: see text]/mg in 32-nm CMOS technology.

Radiation hardness of PantherPix hybrid pixel detector

Hybrid pixel detectors (HPD) are nowadays well known and widely used in fundamental research, e.g. in high energy physics experiments. Over the last decade, segmented semiconductor detectors have also found use in medicine. The total doses received by medical radiation detectors often reach a significant level (up to several hundreds of kGy per decade), especially in applications such as transmission portal in-vivo dosimetry. Such doses might affect detector properties. Therefore, it is necessary to evaluate their performance after absorbing a significant radiation dose. PantherPix is a novel 2D hybrid pixel detector which is designed specifically for use in radiation therapy. As was concluded in earlier studies, it is suitable for radiotherapy quality assurance (QA) and portal dosimetry. In this paper, the PantherPix radiation hardness is investigated using a 60Co source. The dependence on dose of the full depletion voltage, leakage current, detector power consumption and detector response are provided. The PantherPix radiation tolerance has been shown to be adequate for common cumulative doses delivered to radiation detectors in radiotherapy over several decades and its performance has been verified for doses up to 3000 kGy.

Hardness of ionizing radiation fields in MaNGA star-forming galaxies

We investigate radiation hardness within a representative sample of 67 nearby (0.02 ≲ z ≲ 0.06) star-forming (SF) galaxies using the integral field spectroscopic data from the MaNGA survey. The softness parameter η = $\frac{O^{+}/O^{2+}}{S^{+}/S^{2+}}$ is sensitive to the spectral energy distribution of the ionizing radiation. We study η via the observable quantity η′ ($=\frac{[O\rm \small {II}]/[O\rm \small {III}]}{[S\rm \small {II}][S\rm \small {III}]}$) We analyse the relation between radiation hardness (traced by η and η′) and diagnostics sensitive to gas-phase metallicity, electron temperature, density, ionization parameter, effective temperature and age of ionizing populations. It is evident that low metallicity is accompanied by low log η′, i.e. hard radiation field. No direct relation is found between radiation hardness and other nebular parameters though such relations can not be ruled out. We provide empirical relations between log $\rm \eta$ and strong emission line ratios N2, O3N2 and Ar3O3 which will allow future studies of radiation hardness in SF galaxies where weak auroral lines are undetected. We compare the variation of [O iii]/[O ii] and [S iii]/[S ii] for MaNGA data with SF galaxies and H ii regions within spiral galaxies from literature, and find that the similarity and differences between different data set is mainly due to the metallicity. We find that predictions from photoionizaion models considering young and evolved stellar populations as ionizing sources in good agreement with the MaNGA data. This comparison also suggests that hard radiation fields from hot and old low-mass stars within or around SF regions might significantly contribute to the observed η values.

Radiation Hardness of Silicon Carbide upon High-Temperature Electron and Proton Irradiation

The radiation hardness of silicon carbide with respect to electron and proton irradiation and its dependence on the irradiation temperature are analyzed. It is shown that the main mechanism of SiC compensation is the formation of deep acceptor levels. With increasing the irradiation temperature, the probability of the formation of these centers decreases, and they are partly annealed out. As a result, the carrier removal rate in SiC becomes ~6 orders of magnitude lower in the case of irradiation at 500 °C. Once again, this proves that silicon carbide is promising as a material for high-temperature electronics devices.