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A comparative study on the synergistic effect of the total ionizing dose and neutron single event effect on a SiC MOSFET and Si MOSFET was performed based on the 60Co γ source and the high-pressure multiplier 14 MeV neutron source at the China Institute of Atomic Energy. First, a γ-ray total ionizing dose experiment was performed on these two devices, and the differences in the total ionizing dose damage of the SiC and Si MOSFETs were analyzed. Then, neutron single event effect experiments were performed to investigate the effects of different doses on the single event effect for the devices. The results indicate that the unhardened SiC MOSFET has stronger resistance to the total ionizing dose compared with hardened Si MOSFET. During the 14 MeV neutron irradiation experiment, no single event burnout was observed in either device, but single event transients were observed. Even though the hardened Si MOSFETs are capable of suppressing single event transient currents at a higher drain bias, the trapped charge concentration of SiC MOSFETs due to irradiation is smaller than that of Si MOSFETs, which improves their resistance to the total ionizing dose and makes them less affected by the synergistic effect of the total ionizing dose and neutron single event effects. The research results can provide some guidelines for the radiation hardening technology of power devices used in aerospace and nuclear industries. [ABSTRACT FROM AUTHOR]

The synergistic effect of total ionizing dose on single event gate rupture (SEGR) was simulated in the vertical double diffusion metal oxide semiconductor device with SiO2–Si3N4 stacked gate layer. In comparison to the device with a single SiO2 gate layer, the synergistic effect was revealed to be suppressed in the device with SiO2–Si3N4 stacked layer. The mechanism is that the oxide layer is a sensitive area of the SEGR effect. Compared with the single SiO2 layer, the superposition of the additional electric field formed by the trapped holes in the sensitive area of the stacked layer leads to a decrease in the sensitivity of the synergistic effect, which is more obvious with increasing the volume of the Si3N4 layer. [ABSTRACT FROM AUTHOR]

The exposure of spaceborne devices to high-energy charged particles in space results in the occurrence of both a total ionizing dose (TID) and the single-event effect (SEE). These phenomena present significant challenges for the reliable operation of spacecraft and satellites. The rapid advancement of semiconductor fabrication processes and the continuous reduction in device feature size have led to an increase in the significance of the synergistic effects of TID and SEE in static random access memory (SRAM). In order to elucidate the involved physical mechanisms, the synergistic effects of TID and single-event upset (SEU) in a new kind of 130 nm 7T silicon-on-insulator (SOI) SRAM were investigated by means of cobalt-60 gamma-ray and heavy ion irradiation experiments. The findings demonstrate that 7T SOI SRAM is capable of maintaining normal reading and writing functionality when subjected to TID irradiation at a total dose of up to 750 krad(Si). In general, the TID was observed to reduce the SEU cross-section of the 7T SOI SRAM. However, the extent of this reduction was influenced by the heavy ion LET value and the specific writing data pattern employed. Based on the available evidence, it can be proposed that TID preirradiation represents a promising avenue for enhancing the resilience of 7T SOI SRAMs to SEU. [ABSTRACT FROM AUTHOR]

This paper proposes a unique sensor for detecting total ionizing dose (TID) on metal–oxide–semiconductor (MOS) devices. The proposed capacitive radiation sensor is based on commercial 180 nm complementary metal-oxide semiconductor (CMOS) technology. The sensor parameters of 180 nm length (L) and 20 nm oxide thickness (TOX) have been finalized based on simulation and mathematical analysis. Low and high radiation doses ranging from 100 rad to 1 Mrad are used to characterize it. The sensor's sensitivity for 0–10 krad is 20 mV/krad, 10 krad–100 krad is 3.9 mV/krad, and 100 krad–1 Mrad is 0.6 mV/krad when threshold shift is considered into account. Analysis of fixed oxide charge and interface trap charge generation due to ionizing radiation is done. Because interface traps are crucial to device performance, this device is evaluates using traps between 1 E06 cm−3 and 1 E14 cm−3 for realistic performance. Every interface trap exhibits a threshold voltage (VT) shift. Visual technology computer-aided design (TCAD) simulator was used to build, study, and evaluate a capacitive radiation sensor that might be used as a dosimeter for TID monitoring. [ABSTRACT FROM AUTHOR]

TID effects occur in MOS-gated transistors in radiation environments where proton and gamma-rays irradiate the devices. TID effects seriously affect the electrical characteristics of Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET). They can eventually result in the malfunction of power systems when exposed to long-term radiation conditions. We irradiated gamma-rays and protons into 1.2 kV SiC MOSFETs and evaluated the change in electrical properties to analyze the TID's effects. As a result of the experiment, the threshold voltage (VT) and on-resistance (Ron) of 1.2 kV SiC MOSFETs decreased because positive fixed charges inside the oxide increased depending on the radiation dose of the gamma-ray and fluence of the proton irradiations. The degradation of breakdown voltage (BV) occurred owing to a change in the depletion curvature at the edge of termination regions owing to the trapping of the charge in the field's oxide. [ABSTRACT FROM AUTHOR]

We investigated the effects of gate bias regarding the degradation of electrical characteristics during gamma irradiation. Moreover, we observed the punch through failure of 1.2 kV rated commercial Silicon Carbide (SiC) Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) due to the influence of gate bias. In addition, the threshold voltage (VT) and on-resistance (Ron) of the SiC MOSFETs decreased significantly by the influence of gate bias during gamma irradiation. We extracted the concentration of carriers and fixed charge (QF) in oxide using N-type SiC MOS capacitors and Transmission Line Measurement (TLM) patterns to analyze the effects of gamma irradiation. The Total Ionizing Dose (TID) effect caused by high-energy gamma-ray irradiation resulted in an increase in the concentration of holes and QF in both SiC and oxide. To analyze the phenomenon for increment of hole concentration in the device under gate bias, we extracted the subthreshold swing of SiC MOSFETs and verified the origin of TID effects accelerated by the gate bias. The QF and doping concentration of p-well values extracted from the experiments were used in TCAD simulations (version 2022.03) of the planar SiC MOSFET. As a result of analyzing the energy band diagram at the channel region of 1.2 kV SiC MOSFETs, it was verified that punch-through can occur in 1.2 kV SiC MOSFETs when the gate bias is applied, as the TID effect is accelerated by the gate bias. [ABSTRACT FROM AUTHOR]

The space environment is a very harsh operating environment, and space radiation can directly affect the operation of electronic devices causing total ionizing dose (TID), single event effect (SEE) and displacement damage (DD). For most devices TID and SEE are the two most dominant effects, the study of TID and SEE mechanism is one of the main tasks in modern spacecraft design. Previous studies show that there is a synergistic effect between TID and SEE. The TID will significantly affect the sensitivity of the SEE, and the effect rules and mechanisms are not consistent due to the different device process sizes and processes. There are few reports about the synergistic effect of SOI SRAM devices in the world, and the research on SOI SRAM with special memory cell structure has not been carried out. To further elucidate the synergistic effect between TID and SEE in SOI SRAM, an experimental study was conducted using a domestic 130 nm 7T SOI SRAM. The TID and SEE experiments were carried out at the China Institute of Atomic Energy TID test platform and HI-13 tandem accelerator SEE test platform. Before the SEE experiment, three groups of SOI SRAMs were irradiated by total dose of 300, 500 and 750 krad, respectively, and finally the change of the single event upset (SEU) cross section of the SOI SRAM after different doses TID irradiation was obtained. The experimental result shows that the SEU cross section of the SOI SRAM decreases to 80.5%, 66% and 50.5% at three LET values of 13.85, 21.8, and 37.4 MeV·cm2/mg after TID irradiation. There is no obvious difference found in the SEU cross section under different writing modes, which means that the synergistic effect of these devices has no data-dependent. The saturation cross section of the device also shows a trend of decreasing with increasing dose, up to 19.5%, and no significant change in the SEU threshold was found in this study. By analyzing the SEU cross section of flip-flop type 1→0 flip-flop and 0→1 flip-flop, it is found that the delay efficiency of the delay transistor N5 is the main reason for the influence on the SEU cross section. After the mechanism analysis, it is concluded that the delay transistor N5 has an increased equivalent off-state resistance due to the decrease of carrier mobility caused by TID, and this phenomenon is the main reason for the decrease of SEU cross section. The anti-SEE performance of SOI SRAM with special mechanism will be enhanced gradually with longer in-orbit time, which provides new insight for future electronic devices radiation-hardend.

This paper presents a BiCMOS low-noise amplifier (LNA) operating at G-band (140 to 220 GHz) that is robust against harsh operation conditions, namely large temperature variations and radiation exposure. A SiGe technology (IHP’s 0.13- $\mathrm {\mu }$ m SG13G2) has been used for the amplifier design, due to its suitability for millimeter wave (mmW) frequencies and its built-in tolerance to total ionizing dose (TID) radiation. To address the impact of temperature variations on HBTs, the negative temperature dependence of the gain is compensated with a positive temperature dependent collector current, generated by the proposed on-chip and compact (0.0035 mm2) biasing circuit. It has a negligible degradation on the LNA performance, which shows a measured performance comparable with the state of the art with a minimum noise figure (NF) of 9 dB and a gain of 18.1 dB at room temperature, centered around 195 GHz and with a 3-dB bandwidth of 25 GHz. The measured gain and noise figure variations over a −20°C to 80°C temperature range are ±1.1 dB and ±1.5 dB, respectively. Finally, an experiment to study the TID radiation response of mmW LNAs is carried out. Fabricated samples are exposed to 250 krad(Si), 1.5 Mrad(Si) and 2 Mrad(Si), exhibiting a variation smaller than 1 dB in both gain and noise figure.

Deep space exploration, nuclear industry and high energy physics raise higher requirements for the radiation hardness of integrated circuits. However, the existing radiation hardening technologies, such as radiation hardness by design based on bulk silicon technology or silicon-on insulator (SOI) process, are difficult to ensure that the electronics in spacecrafts and nuclear facilities function well in extreme space and nuclear radiation environments. In response to the lack of clear technical paths for the development of ultra-high radiation-hardened chip, a new type of highly radiation-hardened technique was introduced in this paper, named configurable SOI (CSOI). This technology innovatively employs twice bonding and cutting method to fabricate ultra-high radiation hardened 200 mm wafers with embedded configurable silicon layers. The 0-18 μm CSOI complementary metal oxide semiconductor (CMOS) process was successfully developed, which opens up a new route to achieve radiation hardness through in-situ radiation compensation. After the fabrication of CSOI devices, the configuration layer voltage can be tuned flexibly to compensate for the performance degradation due to total ionizing dose (TID) effect and simultaneously suppress the parasitic transistor effect triggered by single event effects (SEE). This helps to improve the radiation hardness of the CSOI transistors. Technology computer aided design (TCAD) simulations validate the tuning mechanism of configurable layer that a negative bias does good to the hardness of both TID and SEE in N-type MOSFET. Based on the CSOI process platform, a design methodology for integrated circuits was developed through assessing the impact of tuning granularity (down to transistor level) and range (from -20 V to 5 V) of configurable layer on the performance and radiation tolerance of static random-access memory (SRAM) cell. Then, the optimized tuning strategy of configurable layer was determined, and a CSOI 4kb SRAM was designed and fabricated with high radiation tolerance. The TID irradiation of the CSOI 4kb SRAM chip was performed at the 60Co gamma irradiation source of Peking University and the SEE experiment was carried out at the Space Environment Simulation and Research Infrastructure (SESRI) in Harbin Institute of Technology. Radiation experiments confirm that the CSOI SRAM achieves up to a level of 6 Mrad(Si) for TID hardness and the threshold of single event upset is greater than 118 (MeV·cm2)/mg, which reaches world-class levels. It is expected to be applied in extreme fields such as deep space exploration and nuclear emergency.

Robotics applications are greatly needed in hazardous locations, e.g., fusion and fission reactors, where robots must perform delicate and complex tasks under ionizing radiation conditions. The drawback is that some robotic parts, such as active electronics, are susceptible to radiation. It can lead to unexpected failures and early termination of the robotic operation. This paper analyses the ionizing radiation effect from 0.09 to 1.5 Gy/s in robotic components (microcontrollers, servo motors and temperature sensors). The first experiment compares the performance of various microcontroller types and their actuators and sensors, where different mitigation strategies are applied, such as using Radiation-Hardened (Rad-Hard) microcontrollers or shielding. The second and third experiments analyze the performance of a 3-Degrees of Freedom (DoF) robotic arm, evaluating its componentsʼ responses and trajectory. This study enhances our understanding and expands our knowledge regarding radiationʼs impact on robotic arms and components, which is useful for defining the best strategies for extending the robotsʼ operational lifespan, especially when performing maintenance or inspection tasks in radiation environments.

Among all the functions that electronics currently perform, clock synthesis has a backbone role. Charge pump phase-locked loops (CP-PLL) are widely used to accomplish clock synthesis thanks to their versatility. One of the most critical parts of CP-PLLs is the charge pump, which greatly influences the system's performance. Even though several high-performance charge pumps have been proposed in the past, with the quick spread of electronics in all the engineering fields, the design of such electronic devices has encountered several additional challenges dictated by external environmental conditions. Examples of these engineering sectors are space, aerospace, industrial, and automotive applications, where the charge pump has to face high environmental temperatures and radiation effects. As a consequence, its design and experimental characterization have to be performed to ensure reliability when operating in harsh conditions. However, to the best of the authors' knowledge, no works in the literature have ever presented a complete charge pump design and characterization in such harsh environments. Therefore, to fill this gap, this paper presents a charge pump for PLL applications specifically designed to reach operating temperatures up to 200 °C and total ionizing dose levels up to 100 Mrad. All design choices have been experimentally verified and are discussed throughout the paper in detail. With the proposed design, we obtained an output current variation of less than 8% at 200 °C and less than 2.5% at 100 Mrad. As opposed to the CPs that can be found in the literature, these results were measured on silicon. The performed measurements confirm that the current variation at 200 °C is better than that of the state-of-the-art CPs operating at lower temperatures, which, moreover, were only simulated. [ABSTRACT FROM AUTHOR]

A system-level total ionizing dose test method of satellite subsystems is discussed in the context of the radiation qualification of a satellite. System-level tests are performed with high-energy X-rays, and the irradiation results of the key subsystems, including the on-board computer, attitude- and orbit-control-system computer, and battery management system, are presented and analyzed in terms of the repeatability of the results, the observability issues, and the importance of the test conditions. Furthermore, the main benefits of the system-level total ionizing dose tests of the given subsystems are discussed, as well as the risks related to performing tests at the system level. [ABSTRACT FROM AUTHOR]

In space applications, electronics must function while being strongly radiated. In this work, the radiation hardness property of the planar two-terminal nanoscale air channel device (NACD), which is a device of vacuum electronics, was demonstrated. Specifically, the total ionizing dose (TID) effect and single-event effects (SEEs) on the NACD were investigated. X-ray and pulse laser were utilized as the sources of TID radiation and SEE radiation, respectively. No significant degradation was observed after 1 Mrad-(Si) X-ray radiation, and no single-event transient phenomenon was detected at the pulse laser energy up to 5 nJ. Additionally, the physical mechanism of radiation hardness in the NACD was illustrated by theoretical analysis and finite element simulation. Taken together, the proposed work shows that the radiation hardness property of the NACD may have a prospect in deep space and nuclear energy applications. [ABSTRACT FROM AUTHOR]

The space radiation environment has a radiation effect on electronic devices, especially the total ionizing dose effect, which seriously affects the service life of spacecraft on-orbit electronic devices and electronic equipment. Therefore, it is particularly important to enhance the radiation resistance of electronic devices. At present, many scientific research institutions still use the areal density equivalent aluminum method to calculate the shielding dose. This paper sets five common metal materials in aerospace through the GEANT4 Monte-Carlo simulation tool MULASSIS, individually calculating the absorption dose caused by single-energy electrons and protons in the silicon detector after shielding of five different materials, which have the same areal density of 0.8097 g/cm2. By comparing the above data, it was found that depending on the particle energy, the areal density aluminum equivalent method would overestimate or underestimate the absorbed dose in the shielded silicon detector, especially for the ionization total dose shielding effect of low-energy electrons. The areal density aluminum equivalent method will greatly overestimate the shielding dose, so this difference needs to be taken into account when evaluating the ionizing dose of the electronics on a spacecraft to make the assessment more accurate. [ABSTRACT FROM AUTHOR]

The application of SiC power devices in the space radiation environment not only requires good resistance to Single Event Effect (SEE) but also requires certain resistance to Total Ionizing Dose (TID) and long-term reliability. Increasing the thickness of the gate oxide layer (tox) can effectively improve the ability of SiC VDMOS to resist SEE. However, it will mainly impact its resistance to TID and Gate Oxide Integrity (GOI). Therefore, this paper compares the influence of tox on the radiation resistance and long-term reliability of SiC VDMOS under the same process and irradiation conditions. The experimental results show that after being irradiated by Cobalt-60 γ-rays, the static parameters of SiC VDMOS devices degrade severely with the increase of the tox; at the same time, the thick gate oxide process will also cause more defects in the gate oxide, leading to the decrease of the gate oxide long-term reliability, but it can be significantly improved after high temperature (HT) accelerated annealing. The research results suggest that the method of increasing tox should take into account the requirements of TID resistance and long-term reliability when improving the SEE radiation resistance of SiC VDMOS. This study is based on the improvement of electrical parameters and the analysis of reliability degradation of SiC VDMOS, providing experimental data support for determining the balance point of tox. [ABSTRACT FROM AUTHOR]

We investigated the effects of gate bias regarding the degradation of electrical characteristics during gamma irradiation. Moreover, we observed the punch through failure of 1.2 kV rated commercial Silicon Carbide (SiC) Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) due to the influence of gate bias. In addition, the threshold voltage (VT) and on-resistance (Ron) of the SiC MOSFETs decreased significantly by the influence of gate bias during gamma irradiation. We extracted the concentration of carriers and fixed charge (QF) in oxide using N-type SiC MOS capacitors and Transmission Line Measurement (TLM) patterns to analyze the effects of gamma irradiation. The Total Ionizing Dose (TID) effect caused by high-energy gamma-ray irradiation resulted in an increase in the concentration of holes and QF in both SiC and oxide. To analyze the phenomenon for increment of hole concentration in the device under gate bias, we extracted the subthreshold swing of SiC MOSFETs and verified the origin of TID effects accelerated by the gate bias. The QF and doping concentration of p-well values extracted from the experiments were used in TCAD simulations (version 2022.03) of the planar SiC MOSFET. As a result of analyzing the energy band diagram at the channel region of 1.2 kV SiC MOSFETs, it was verified that punch-through can occur in 1.2 kV SiC MOSFETs when the gate bias is applied, as the TID effect is accelerated by the gate bias.

Studying the effects of gamma radiation on the instrumentation and control (I&C) system of a nuclear power plant is critical to the successful and reliable operation of the plant. In the accidental scenario, the adverse environment of ionizing radiation affects the performance of the I&C system and it leads to inaccurate and incomprehensible results. This paper reports the effects of gamma radiation on the AT89C51RD2, a commercial-off-the-shelf 8-bit high-performance flash microcontroller. The microcontroller, selected for the device under test for this study is used in the remote terminal unit for a nuclear power plant. The custom circuits were made to test the microcontroller under different gamma doses using a 60Co gamma source in both ex-situ and in-situ modes. The device was exposed to a maximum dose of 1.5 kGy. Under this hostile environment, the performance of the microcontroller was studied in terms of device current and voltage changes. It was observed that the microcontroller device can operate up to a total absorbed dose of approximately 0.6 kGy without any failure or degradation in its performance.

As robotics become more sophisticated, there are a growing number of generic systems being used for routine tasks in nuclear environments to reduce risk to radiation workers. The nuclear sector has called for more commercial-off-the-shelf (COTS) devices and components to be used in preference to nuclear specific hardware, enabling robotic operations to become more affordable, reliable, and abundant. To ensure reliable operation in nuclear environments, particularly in high-gamma facilities, it is important to quantify the tolerance of electronic systems to ionizing radiation. To deliver their full potential to end-users, mobile robots require sophisticated autonomous behaviors and sensing, which requires significant computational power. A popular choice of computing system, used in low-cost mobile robots for nuclear environments, is the UP Core single board computer. This work presents estimates of the total ionizing dose that the UP Core running the Robot Operating System (ROS) can withstand, through gamma irradiation testing using a Co-60 source. The units were found to fail on average after 111.1 ± 5.5 Gy, due to faults in the on-board power management circuitry. Its small size and reasonable radiation tolerance make it a suitable candidate for robots in nuclear environments, with scope to use shielding to enhance operational lifetime.

Ionizing radiation induces defects in STI oxides in current MOSFETs. These defects may degrade the performance of the MOS circuit. Analytical models for the buildup of these defects during the radiation exposure are available in literature. In this paper, we introduce an improved model to estimate the buildup of defects that is valid for both low and high radiation doses. Our improved model is compared to published data showing its validity.

Perovskite CsPbBr3 semiconductors exhibit unusually high defect tolerance leading to outstanding and unique optoelectronic properties, demonstrating strong potential for γ-radiation and X-ray detection at room temperature. However, the total dose effects of the perovskite CsPbBr3 must be considered when working in a long-term radiation environment. In this work, the Schottky type of perovskite CsPbBr3 detector was fabricated. Their electrical characteristics and γ-ray response were investigated before and after 60Co γ ray irradiation with 100 and 200 krad (Si) doses. The γ-ray response of the Schottky-type planar CsPbBr3 detector degrades significantly with the increase in total dose. At the total dose of 200 krad(Si), the spectral resolving ability to γ-ray response of the CsPbBr3 detector has disappeared. However, with annealing at room temperature for one week, the device's performance was partially recovered. Therefore, these results indicate that the total dose effects strongly influence the detector performance of the perovskite CsPbBr3 semiconductor. Notably, it is concluded that the radiation-induced defects are not permanent, which could be mitigated even at room temperature. We believe this work could guide the development of perovskite detectors, especially under harsh radiation conditions. [ABSTRACT FROM AUTHOR]

The excellent performance and radiation-hardness potential of carbon nanotube (CNT) field effect transistors (CNTFETs) have attracted wide attention. However, top-gate structure CNTFETs, which are often used to make high-performance devices, have not been studied enough. In this paper, the total ionizing dose (TID) effect of the top-gate structure CNTFETs and the influence of the substrate on top-gate during irradiation are studied. The parameter degradation caused by the irradiation- and radiation-damage mechanisms of the top-gate P-type CNTFET were obtained by performing a Co-60 γ-ray irradiation test. The results indicate that the transfer curves of the top-gate P-type CNTFETs shift negatively, the threshold voltage and the transconductance decrease when TID increases, and the subthreshold swing decreases first and then increases with the increase in TID. The back-gate transistor is constructed by using the substrate as a back-gate, and the influence of back-gate bias on the characteristics of the top-gate transistor is tested. We also test the influence of TID irradiation on the characteristics of back-gate transistors, and reveal the effect of trapped charge introduced by radiation on the characteristics of top-gate transistors. In addition, the CNTFETs that we used have obvious hysteresis characteristics. After irradiation, the radiation-induced trapped charges generated in oxide and the OH groups generated by ionization of the CNT adsorbates aggravate the hysteresis characteristics of CNTFET, and the hysteresis window increases with the increase in TID. [ABSTRACT FROM AUTHOR]

The total ionizing dose sensitivity of planar 150 nm CMOS technology is evaluated by measuring the DC responses of nMOSFETs at several irradiation steps up to 125 krad(SiO2). Different TID sensitivities are measured for transistors built with different channel dimensions and operating voltages (I/O and core). The experimental results evidence strong relations between TID sensitivity and the doping profiles in the channel. I/O transistors have the highest TID sensitivity due to their thicker gate oxide and lower bulk doping compared with core devices. In general, narrow-channel devices have the worst degradation with negative threshold voltage shifts, transconductance variations and increased subthreshold leakage currents, suggesting charge trapping in shallow trench isolation (STI). The enhanced TID tolerance of short-channel core devices is most likely related to the increased channel doping induced by the overlapping of halo implantations. Finally, transistors fabricated for low-leakage applications exhibit near insensitivity to TID due to higher bulk doping used during the fabrication to minimize the drain-to-source leakage current. [ABSTRACT FROM AUTHOR]

In this work, the authors investigated the influence of proton-irradiation on the dark current of XBp longwave infrared InAs/GaSb type-II superlattice barrier detectors, showing a cutoff wavelength from 11 µm to 13 µm at 80 K. The proton irradiations were performed with 63 MeV protons and fluences up to 8·1011 H+/cm² on a type-II superlattice detector kept at cryogenic (100 K) or room temperature (300 K). The irradiation temperature of the detector is a key parameter influencing the effects of proton irradiation. The dark current density increases due to displacement damage dose effects and this increase is more important when the detector is proton-irradiated at room temperature rather than at cryogenic temperature. [ABSTRACT FROM AUTHOR]

This work investigates the cumulative dose 60Co gamma ( $\gamma$ ) – ray irradiation effects on enhancement mode HEMT devices inheriting 3D – Electron and Hole Gases for dosimeter applications. The devices are irradiated through a 60Co source and demonstrate the enhancement in the drain current metrics. To elucidate, the said devices were irradiated through different mechanisms and the Compton effect was investigated through contour plots via TCAD simulations. The degradation of Schottky Gate contact and insulator charging affects the 2D – Hole Gas at the GaN cap and thereby affects the bottleneck at the 3DEG sheet. This significantly affects the OFF – state leakage components of the said device and can therefore be exploited for potential use in sensing and dosimeter applications. The leakage components can be exploited further to improve the linearity of the dosimeter by considering different grading profiles of the AlGaN layer. In this regard, a workflow for optimizing the sensitivity and linearity of the dosimeter through different graded profiles is also presented. Amongst all, gaussian graded profiles have been identified as the best – case scenario considering the sensitivity and exhibiting a linear operation.

The impact of ring-shaped collector contact (RCC) on total ionizing dose (TID) susceptibility of 40-V vertical n-p-n bipolar transistors is investigated. The 60Co $\gamma $ -ray irradiation experiment shows that the devices with RCC suffer less current gain degradation than their counterparts with conventional collector contact structure, which is independent of the emitter area and bias condition during irradiation. Technology computer-aided design (TCAD) simulation results indicate that the enhancement in radiation tolerance of the RCC devices should be attributed to the mitigation of trap-assisted carrier recombination at the Si/SiO2 interfaces near emitter–base (EB) junction rather than the concentration or distribution variations of radiation-induced traps. Moreover, the mitigation of carrier recombination in RCC devices could result from the creation of new current flow paths that suppress the diffusion of injected electrons toward the trap-enriched Si/SiO2 interfaces. [ABSTRACT FROM AUTHOR]

A novel methodology for total ionizing dose (TID) hardening of Silicon-on-insulator (SOI) MOSFET is demonstrated by employing a superior type of void embedded SOI (VESOI) substrate. With the successful removal of most of the radiation sensitive area in buried oxide, the TID tolerance of VESOI MOSFET is significantly enhanced in comparison to its conventional SOI counterpart. In particular, the shift of threshold voltage (${V}_{\text {th}}$) and subthreshold swing is only −38.9mV and 11.6mV/dec at radiation doses up to 2Mrad(Si). Further device simulation shows that the radiation immunity can withstand misalignment between the gate and embedded void in a wide range. Our VESOI substrates, offering both high compatibility with planar CMOS process and versatile void embedded device design, exhibit great potential in the development of anti-radiation SOI devices. [ABSTRACT FROM AUTHOR]

A research of total ionizing dose and annealing effects on Schottky type p-GaN gate Al0.2Ga0.8N/GaN high electron mobility transistors (HEMTs) has been carried out. Devices with breakdown voltages of 100V/200V/650V were irradiated under Co-60 X-rays. Radiation doses reach to a total amount of 500 krad (Si) with dose rate of 50 rad(Si)/s under gate biases of ${V}_{GS}=0\text{V}$ /+3V/+5V. Negative threshold voltage shifts were observed, especially under positive gate biases. It is found out that the threshold voltage shifts are due to the accumulation of positive charges (holes) trapped in the interface of p-GaN/AlGaN. Therefore, the shift amount is proportional to the gate bias and the radiation amount, while not related to the breakdown voltage. After the total ionizing dose experiments, both high temperature and room temperature annealing processes were taken. During the annealing processes, the shifted threshold voltage recovered, and high temperature accelerated the recovery process. Experiment results indicate that the total ionizing dose effect is recoverable. [ABSTRACT FROM AUTHOR]

The impact of gamma radiation on a commercial off the shelf microcontroller board has been investigated. Three different tests have been performed to ascertain the radiation tolerance of the device from a nuclear decommissioning deployment perspective. The first test analyses the effect of radiation on the output voltage of the on-board voltage regulator during irradiation. The second test evaluated the effect of gamma radiation on the voltage characteristics of analogue and digital inputs and outputs. The final test analyses the functionality of the microcontroller when using an external, shielded voltage regulator instead of the on-board voltage regulator. The results suggest that a series of latch-ups occurs in the microcontroller during irradiation, causing increased current drain which can damage the voltage regulator if it does not have short-circuit protection. The analogue to digital conversion functionality appears to be more sensitive to gamma radiation than digital and analogue output functionality. Using an external, shielded voltage regulator can prove beneficial when used for certain applications. The collected data suggests that detaching the voltage regulator can extend the lifespan of the platform up to approximately 350 Gy.

This paper presents a novel MOSFET layout named the "hourglass transistor", aimed to improve its electrical behavior under Total Ionizing Dose (TID) effects. The new radiation-tolerant device is based on augmenting parasitic channel resistance, alteration of the electric field by the longitudinal corner effect (LCE), and reducing channel resistance within the central gate region. The radiation-robust MOS structure design was implemented in a 130 nm CMOS bulk process and its performance was analyzed through simulations using 3D physical models. The proposed hourglass transistor was compared with rectangular, diamond, dog bone and H-gate devices, showing a reduction in the post-radiation I o f f current of 8.77, 4.6, 1.85 and 13.7 times, respectively; and a pre-radiation normalized saturation current of 2.29, 1.04, 1.58 and 1.52 times greater with an increase of 4.84, 1, 2.47 and 2.03 times the gate area, respectively. [ABSTRACT FROM AUTHOR]

The combined effect of total ionization dose (TID) and time-dependent dielectric breakdown (TDDB) of partially depleted silicon-on-insulator (PDSOI) NMOSFET is investigated. First, the effect of TDDB on the parameter degradation of the devices was investigated by accelerated stress tests. It is found that TDDB stress leads to a decrease in off-state current, a positive drift in threshold voltage, and a reduction of maximum transconductance. Next, the degradation patterns of TID effect on the devices are obtained. The results show that the parameter degradation due to gamma radiation is opposite to the TDDB stress. Finally, the combined effect of TID and TDDB is investigated. It is found that the drift of the devices' sensitive parameters due to TDDB stress decreases in a total dose of gamma radiation environment. The TDDB lifetime is shortened, but the pattern of gate current change remains unchanged. The failure mechanism of the gate oxide layer under TDDB stress is not changed after irradiation. [ABSTRACT FROM AUTHOR]

Total-ionizing-dose (TID) effects are investigated in a highly-scaled gate-all-around (GAA) FET technology using Si nanowire channels with a diameter of 8 nm. n- and p-FETs are irradiated up to 300 Mrad(SiO2) and annealed at room temperature. TID effects are negligible up to 10 Mrad(SiO2). At ultrahigh doses, the TID degradation depends on the irradiation bias condition, with more severe effects observed in longer channel devices. The worst case irradiation condition is when positive bias is applied to the gate. Threshold-voltage shifts are caused by H+-driven generation of interface traps at the oxide/channel interface. In contrast, FETs irradiated under negative gate bias are dominated by transconductance loss and increases of low-frequency noise, suggesting the activation of border traps. Enhanced off-leakage current is observed in n-FETs due to charge trapping in shallow-trench isolation, and in p-FETs due to trap-assisted recombination at STI sidewalls and/or spacer dielectrics at drain/bulk junctions. [ABSTRACT FROM AUTHOR]

In this work, the effect of Total Ionizing Dose (TID) on the performance of GaN on Si MIS-HEMT power devices with in-situ SiN cap layer is investigated. 13 samples were exposed to different accumulated dose (100 krad and 400 krad) of Co $^{60}~\gamma $ -ray irradiation with two bias conditions (grounded and stressed). The characteristics of the devices after irradiation experiment were evaluated by measuring VTH shift, on-resistance (RON), and dynamic RON. A comprehensive study of TID effects are demonstrated in this article to verify different mechanisms and their interactions. Simulations using PHITs were also carried out to further confirm the damages in the epitaxial structure by the accumulated dose. [ABSTRACT FROM AUTHOR]

CMOS image sensor (CIS) cameras are common imaging devices, compared with charge coupled device (CCD), CIS has unique advantages such as small size, high integration, low power consumption and lightweight. In the process of monitoring in the nuclear industry environment, the CIS and camera motherboard are vulnerable to noise caused by gamma radiation, which can affect the imaging resolution of the image. Therefore, it is necessary to evaluate the anti�radiation ability of CIS camera from a systematic perspective and analyze different test methods of camera resolution after irradiation. By using 60Co�γ radiation source to irradiate CIS camera, the irradiated CIS camera was combined with irradiated mainboard and unirradiated mainboard to form different cameras, and the two kinds of cameras were tested. The following data can be obtained from camera tests, such as, the relationship between dark current and cumulative dose of CIS after irradiation, the relationship between resolution value and cumulative dose under different test methods based on ISO 12233 standard, the relationship between the number of noise points in the minimum gray value area and the maximum gray value area of the target area of the test card image collected by the camera, the relationship between the average number of noise points in the whole target area and the cumulative dose, and the relationship between the gray value of the resolution test card and the cumulative dose. The functional relationship between noise and modulation transfer function (MTF) of the irradiated imaging system was established through the theoretical derivation of MTF, by putting the gray values of the resolution test card under different cumulative doses into formulas to obtain the functional relationship between the radiation dose of the calculated MTF value. Finally, by analyzing the theoretical calculation and the actual measurement of MTF value, the functional relationship between noise and image resolution and radiation dose of the typical CIS camera was obtained, and then the upper limit of radiation dose of the CIS camera under the corresponding resolution was obtained. The results show that both CIS noise and camera motherboard noise have an impact on camera resolution, and the noise increases with the increase of cumulative dose. The total ionization dose of the camera is less than 150 krad(Si), camera resolution is not decrease significantly. In ISO 12233 eSFR resolution test, it is found that it is more reasonable to evaluate the resolution parameters of the irradiated camera by using aliasing onset based on the wedge pattern test than the SFR test method.

The effects of total ionizing dose (TID) on static random access memory (SRAM) physical unclonable functions (PUFs) are studied through X-ray and proton irradiation of commercially available SRAM. Negative shifts in the fractional Hamming weight (FHW) were measured with increasing TID, indicating a migration of bistable cells toward logic low. Additionally, positive shifts in the intra-die fractional Hamming distance (FHD) were measured and indicate changes to the virtual fingerprint of an SRAM PUF with TID, especially in devices that were dosed while holding data. Shifts in inter-die FHD were negligible, allowing individual SRAMs still to be easily identified based on the FHD between a known and unknown sample even after moderate amounts of TID. In some cases, SRAMs could still be identified by their PUFs after the devices had failed. In all cases, the irradiated SRAM devices retained their virtual fingerprint after recovery through annealing. [ABSTRACT FROM AUTHOR]

This article studies the radiation effects on the junction leakage random telegraph signal (JL-RTS). Using arrays of transistors, a statistical study of the phenomenon in MOSFETs source p-n junctions is performed and the impact of the electric field, the type of irradiation, and the source design is investigated. It appears that although JL-RTS originates both from the displacement damage dose (DDD)- and total ionizing dose (TID)-induced defects, the latter is the dominant contribution in MOSFETs sources due to an electric field enhancement (EFE). This article then completes the study with ab initio molecular simulations to investigate the origin of the JL-RTS. The results advocate for the adoption of the structural fluctuation model over the state charge fluctuation model to describe the origin of the phenomenon. [ABSTRACT FROM AUTHOR]

The n-type ultrathin fully depleted silicon-on-insulator (FDSOI) metal–oxide–semiconductor field-effect transistors (MOSFETs), with a Hf0.5Zr0.5O2 high dielectric permittivity (high-k) dielectric as gate insulator, were fabricated. The total ionizing dose effects were investigated, and an X-ray radiation dose up to 1500 krad(Si) was applied for both long- and short-channel devices. The short-channel devices (0.025–0.100 μm) exhibited less irradiation sensitivity compared with the long-channel devices (0.35–16 μm), leading to a 71% reduction in the irradiation-induced drain current growth and a 26% decrease in the shift of the threshold voltage. It was experimentally demonstrated that the OFF mode is the worst case among the three working conditions (OFF, ON and All0) for short-channel devices. Also, the determined effective electron mobility was enhanced by 38% after X-ray irradiation, attributed to the different compensations for charges triggered by radiation between the high-k dielectric and buried oxide. By extracting the carrier mobility, gate length modulation, and source/drain (S/D) parasitic resistance, the degradation mechanism on X-ray irradiation was revealed. Finally, the split capacitance–voltage measurements were used to validate the analysis. [ABSTRACT FROM AUTHOR]

The total ionizing dose response of nanosheet gate-all-around metal-oxide-semiconductor field effect transistor (NS GAA MOSFET) fabricated on novel void-embedded silicon on insulator (VESOI) substrate was investigated in this work. Strong radiation tolerance with as small as 46.6mV threshold voltage shift and non-discernable increase of off-state current were observed even at a dose of 7Mrad(Si) X-ray irradiation. Both the experiment and simulation results reveal that the radiation tolerance of the MOSFET device can be inherently attributed to the GAA channel. Our work undoubtedly demonstrates that the NS GAA device on VESOI substrate has great potential for radiation-harden applications under heavy radiation environment. [ABSTRACT FROM AUTHOR]

LabOSat-01 is a payload designed to perform characterization experiments on electronic devices in hostile environments. Both Commercial-Off-The-Shelf components and custom nano and micro devices were studied in the last decade with this platform. The Total Ionizing Dose (TID) received by small satellites in Low Earth Orbit was measured with LabOSat-01 using p-MOSFET COTS and the results are presented in this work. Measurements were performed on two satellite missions, each totaling 1100 days, launched three years apart. Dosimeters were integrated in different satellite positions, with different shielding, and the measured TID after 1100 days ranged from 5 Gy to 19 Gy. [ABSTRACT FROM AUTHOR]

This paper presents experimental and numerical analysis of a buried P-pillar (BP) lateral double-diffused metal-oxide semiconductor (LDMOS) fabricated on a silicon-on-insulator (SOI) substrate. The experimental results indicate that the specific on-resistance ($R_{ {on,sp}}$) of the SOI BP-LDMOS is 9.5 $\text{m}\Omega \cdot {\mathrm{ cm}}^{{2}}$ with a breakdown voltage (BV) of 229 V, which corresponds to a figure of merit (FOM) of 5.52 MW/cm2. The analysis of structural parameter optimization of the SOI BP-LDMOS under different doping concentrations in the drift region and P-pillar layer is conducted via numerical simulation. The results show that the tested sample can achieve about 80% of the maximal FOM. Finally, the experimental and numerical investigation of the total ionizing dose (TID) radiation effect on the BV shift is performed. The TID tolerance of the measured SOI BP-LDMOS can reach 300 krad(Si) to support a voltage of 200 V. Due to the electric field modulation hardening design, compared with the conventional hardened SOI LDMOS, the studied hardened BP-LDMOS can achieve a significant improvement in the TID tolerance from 225 krad(Si) to 525 krad(Si). [ABSTRACT FROM AUTHOR]

The contribution of low-energy particles down to ~200 eV to the dose deposited on the very near surface of materials subject to the space environment is investigated by means of GEANT4 Monte Carlo simulations. The contribution to the dose, of the low-energy parts of Global Radiation Earth ENvironment (GREEN) spectra (200 eV–40 keV for electrons, 200 eV–100 keV for protons), is compared with calculations performed with AE8/AP8. Both geostationary earth orbit (GEO) and low earth orbit (LEO) SPOT like orbits are studied. The dose depth profiles are estimated for silicon material. The impact on the dose calculation of different transport models is also investigated. Below 1 keV, the relevance of continuous processes is analyzed for electrons by comparison with a discrete model [GEANT4/microelectronic (MICROELEC)]. This analysis is also performed for protons below 10 keV. [ABSTRACT FROM AUTHOR]

The effects of total dose irradiation on graphene-based Hall sensors were investigated by 60Co $\gamma $ -ray in this paper. The basic electrical parameters of the sensors were measured before and after $\gamma $ -ray irradiation up to 1 Mrad(Si). Decreases in the Hall voltage, linearity and current-related sensitivity in response to $\gamma $ -ray irradiation were observed. With the help of Raman spectroscopy and X-ray photoelectron spectra (XPS), the degradation after irradiation was attributed to the introduction of defects and the increase in doping concentrations in the graphene layer. Moreover, the introduction of defects and impurities enhanced the Coulomb scattering of carriers, resulting in a decrease in mobility, which in turn affected the sheet resistance. This work provides an insight into the interactions of ionizing irradiation with graphene-based Hall sensors, which could be applied in space or other irradiation sensitive applications. [ABSTRACT FROM AUTHOR]

The combined effect of total ionization dose (TID) and time-dependent dielectric breakdown (TDDB) of partially depleted silicon-on-insulator (PDSOI) NMOSFET is investigated. First, the effect of TDDB on the parameter degradation of the devices was investigated by accelerated stress tests. It is found that TDDB stress leads to a decrease in off-state current, a positive drift in threshold voltage, and a reduction of maximum transconductance. Next, the degradation patterns of TID effect on the devices are obtained. The results show that the parameter degradation due to gamma radiation is opposite to the TDDB stress. Finally, the combined effect of TID and TDDB is investigated. It is found that the drift of the devices’ sensitive parameters due to TDDB stress decreases in a total dose of gamma radiation environment. The TDDB lifetime is shortened, but the pattern of gate current change remains unchanged. The failure mechanism of the gate oxide layer under TDDB stress is not changed after irradiation.

This article presents a radiation-hardened Cortex-R4F system-on-chip prototype with integrated total ionizing dose (TID) dynamic compensation capabilities, designed and fabricated in 28-nm fully depleted silicon-on-insulator (FD-SOI) technology. The processor was made robust to single-event effects, thanks to several design techniques: error correcting code (ECC) protected and bit-interleaved memories, optimized radiation-hardened sequential cells, and sensitive logic cells filtering. To counter the TID effects on the processor functionality and performances, the system embeds an integrated digital dosimeter. The dosimeter is capable of computing the TID in real time and providing the information to the system. Using a software lookup table (LUT), coupled with 28-nm FD-SOI technology support of asymmetric and wide-body-biasing, the reported TID can be converted to a request made to an external body-bias generator and be fully compensated. The system, operating at 0.9 V and 500 MHz, was tested under space grade radiations and has shown no failure in the 0 krad(Si) to 50 krad(Si) TID range. [ABSTRACT FROM AUTHOR]

Total ionizing dose response of 14-nm bulk-Si FinFETs has been studied with a specially designed test chip. The radiation testing shows evidence of interface trap build-up on 14-nm Bulk FinFET technologies. These defects created in the isolation layer give rise to a new radiation-induced leakage path which might lead to a reliability issue in CMOS technologies at or below the 14-nm node. TCAD simulations are performed and an analytical model for TID-induced leakage current is presented to support analysis of the identified TID mechanism. TCAD simulation and analytical model results are consistent with the experimental data. [ABSTRACT FROM AUTHOR]