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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]

Negative-bias-stress and total-ionizing-dose (TID) effects in deeply scaled Ge-gate-all-around (GAA) nanowire (NW) devices are characterized for different biasing conditions. Negative-bias-stress-induced degradation in Ge GAA device originates primarily from the interface- and border-trap generation. Devices stressed at high gate voltage show rapid initial degradation and quick saturation dominated by interface-trap generation. Radiation-induced OFF-state leakage current in Ge GAA NWs increases with dose due to enhanced band-to-band tunneling (BTBT) caused by charge trapping in the shallow trench isolation (STI). [ABSTRACT FROM AUTHOR]

A method of analyzing ion-induced reverse leakage current in SiC power devices is described. The resulting methodology enables the estimation of the proportion of ion strikes that produce step increases in leakage current as well as distributions of sensitive die areas relative to leakage step magnitude. These results are compared across various bias and ion linear energy transfer combinations to isolate the influence of each variable. [ABSTRACT FROM AUTHOR]

Analog-to-digital converters (ADCs) with different topologies respond differently to total ionizing dose (TID). A flexible behavioral modeling approach is proposed for system-level simulation of TID effects in successive-approximation-register (SAR) ADCs. The radiation-enabled approach can be adapted for a wide range of ADCs of various resolutions, clock speeds, and manufacturers. The empirical model is calibrated and validated, pre-rad and post-rad, for a particular ADC. Pre-rad calibration is performed by introducing distributions of static parameters corresponding to datasheet specifications. The post-rad calibration is accomplished by introducing error sources associated with the comparator and digital-to-analog converter (DAC), corresponding to experimental data. The calibrated model is used to examine the dynamic performance and to estimate the probability of parametric failure during the mission lifetime. [ABSTRACT FROM AUTHOR]

The onset of ion-induced reverse leakage current in SiC Schottky diodes is shown to depend on material properties, ion linear energy transfer (LET), and bias during irradiation, but not the voltage rating of the parts. This is demonstrated experimentally for devices from multiple manufacturers with voltage ratings from 600 to 1700 V. Using a device with a higher breakdown voltage than required in the application does not provide increased robustness related to leakage current degradation, compared to using a device with a lower voltage rating. [ABSTRACT FROM AUTHOR]

Irradiation of 2N5339 n-p-n bipolar junction transistors (BJTs) with either 250-MeV protons or 10-keV X-rays shifts the input characteristics to lower values of $V_{\mathrm {BE}}$ while degrading the current gain and drive current. The degradation is consistent with increased recombination in the neutral base and emitter–base (E–B) depletion region. A decrease in collector current following proton irradiation suggests that recombination in the neutral base is significant. At a given ionizing dose, degradation is worse for proton irradiation than for X-ray irradiation due to the presence of displacement damage and a higher charge yield. A comparison of degradation produced by the two radiation sources suggests that ~40% of the excess base current resulting from 250-MeV proton irradiation is due to ionization damage. When compared with previous results for other devices, these results suggest that ionization-to-displacement damage ratios in bipolar devices may increase with proton energy in a way that is consistent with trends in charge yield and non-ionizing energy loss (NIEL). [ABSTRACT FROM AUTHOR]

Gate and drain bias dependences of hot carrier degradation are evaluated for AlGaN/GaN HEMTs fabricated via two different process methods. Both positive and negative threshold voltage $V_{\mathbf{th}}$ shifts are observed for each device type, depending on the mode and duration of the stress, indicating the presence of significant densities of donor-like and acceptor-like traps. Worst-case stress bias for transconductance degradation is the “ON” state for both device types. We find that transconductance degradation provides a more effective parameter to monitor defect buildup than $V_{\mathbf{th}}$ shifts, and that a single worst-case stressing bias condition cannot be defined for all varieties of AlGaN/GaN HEMTs. Low-frequency noise measurements versus temperature assist the identification of defects responsible for the observed degradation. Defect dehydrogenation and oxygen impurity centers are found to be particularly significant to the response of these devices. [ABSTRACT FROM AUTHOR]

The radiation response of complementary metal–oxide–semiconductor (CMOS) gate oxides is typically insensitive to true dose-rate effects, but damage in deep-sub-micrometer technologies is dominated by ionization mechanisms in thick isolation oxides surrounding the transistors. Recent results in 65-nm FETs demonstrated that performance degradation in ultrahigh total ionizing dose (TID) experiments is due to defects in the isolation shallow trench isolation oxide or in the materials composing the lightly doped drain spacers. These insulators are thick, deposited, and crossed by a low electric field, characteristics similar to those typical of passivation oxides in linear bipolar technologies for which an enhanced low-dose-rate sensitivity (ELDRS) has been observed and systematically studied. We report in this paper the clear evidence of a dose-rate sensitivity of the TID-induced damage in both 130- and 65-nm CMOS technologies exposed to different radiation sources (X-rays and $\gamma $ -rays from a 60Co source). This sensitivity is attributed to mechanisms similar to those explaining ELDRS in bipolar devices and represents a significant challenge to the definition of a qualification procedure for circuits to be used in extreme radiation environments. [ABSTRACT FROM AUTHOR]

We demonstrate the utility of focused, pulsed X-rays for investigating localized total ionizing dose effects in bipolar analog integrated circuits. Using the LM139 comparator as a test vehicle, we show how the technique can be used to identify the sources of degradation as a result of irradiating different transistors of the device and how this impacts the input bias current, input offset voltage, and output voltage. The 2-D mapping of the sensitive regions of transistors is presented, where the results of localized irradiation impact the monitored operational parameters. [ABSTRACT FROM PUBLISHER]

A bipolar-transistor-based sensor technique has been used to compare silicon displacement damage from known and unknown neutron energy spectra generated in nuclear reactor and high-energy-density physics environments. The technique has been shown to yield 1-MeV(Si) equivalent neutron fluence measurements comparable to traditional neutron activation dosimetry. This paper significantly extends previous results by evaluating three types of bipolar devices utilized as displacement damage sensors at a nuclear research reactor and at a Pelletron particle accelerator. Ionizing dose effects are compensated for via comparisons with 10-keV X-ray and/or cobalt-60 gamma ray irradiations. Nonionizing energy loss calculations adequately approximate the correlations between particle and device responses and provide evidence for the use of one particle type to screen the sensitivity of the other. [ABSTRACT FROM PUBLISHER]

The degradation induced by ultrahigh total ionizing dose in 65-nm MOS transistors is strongly gate-length dependent. The current drive decreases during irradiation, and the threshold voltage often shifts significantly during irradiation and/or high-temperature annealing, depending on transistor polarity, applied field, and irradiation/annealing temperature. Ionization in the spacer oxide and overlying silicon nitride layers above the lightly doped drain extensions leads to charge buildup as well as the ionization and/or release of hydrogen. Charge trapped in the spacer oxide or at its interface modifies the parasitic series resistance, reducing the drive current. The released hydrogen transports as H+ with an activation energy of ~0.92 eV. If the direction of the electric field is suitable, the H+ can reach the gate oxide interface and depassivate Si-H bonds, leading to threshold voltage shifts. Newly created interface traps are most prominent near the source or drain. The resulting transistor responses and defect-energy distributions often vary strongly in space and energy as a result, as demonstrated through current–voltage, charge-pumping, and low-frequency noise measurements. [ABSTRACT FROM PUBLISHER]

Heavy-ion-induced degradation in the reverse leakage current of SiC Schottky power diodes exhibits a strong dependence on the ion angle of incidence. This effect is studied experimentally for several different bias voltages applied during heavy-ion exposure. In addition, TCAD simulations are used to give insight on the physical mechanisms involved. [ABSTRACT FROM PUBLISHER]

This paper investigates the effects of gamma radiation on the operation of commercially available capacitive microelectromechanical accelerometers intended for use in robotic systems deployed for nuclear disaster remediation. Radiation-induced accelerometer degradation is examined in terms of its effects on the input–output relationship of ADXL325 accelerometers (Analog Devices, Inc., Norwood, Massachusetts, USA) prior to sensor failure. Results show a moderate increase in sensor nonlinearity as well as significant, non-monotonic changes to accelerometer axis sensitivity and zero- $g$ bias. Both part-to-part variation and axis-to-axis variation within individual accelerometers are observed. The effects of the observed accelerometer degradation on the performance of a simple robotic manipulator that relies on acceleration feedback are evaluated in simulation. Additionally, using tools derived from adaptive control theory, this paper presents a real-time recalibration technique for mitigating the effects of the measured accelerometer degradation on the performance of robotic systems that can be applied in-field, without the knowledge of the degradation mechanisms. An example implementation of this technique is also evaluated. Results suggest that control-based strategies for mitigating hardware degradation may be able to extend the useful operating lifetime of non-radiation-hardened sensors in robotic systems deployed in extreme radiation environments. [ABSTRACT FROM PUBLISHER]

We have characterized the total ionizing dose response of strained Ge p MOS FinFETs built on bulk Si using a fin replacement process. Devices irradiated to 1.0 Mrad(SiO2) show minimal transconductance degradation (less than 5%), very small \text {V}_{th} shifts (less than 40 mV in magnitude) and very little ON/OFF current ratio degradation (<5%), and only modest variation in radiation response with transistor geometry (typically less than normal part-to-part variation). Both before and after irradiation, the performance of these strained Ge p$ MOS FinFETs is far superior to that of past generations of planar Ge $p$ MOS devices. These improved properties result from significant improvements in processing technology, as well as the enhanced gate control provided by the strained Ge FinFET technology. [ABSTRACT FROM PUBLISHER]

Responses to 1.8 MeV proton irradiation and 10-keV X-ray irradiation under typical bias conditions are investigated for AlGaN/GaN HEMTs fabricated with different types of process technologies. We find that, in contrast to previous generations of process technologies, total ionizing dose effects can be significant in these devices. For proton irradiation, worst-case bias for transconductance degradation for GaN-on-SiC substrate devices is ON bias, and for devices built on free-standing GaN substrates, the worst-case bias condition is semi-ON bias. Low-frequency noise measurements demonstrate that these differences result from differences in defect types and energy distributions for the different types of devices, both before and after irradiation. These results emphasize the need to test devices under a wide range of conditions during characterization and qualification testing. [ABSTRACT FROM PUBLISHER]

Experimental results on ion-induced leakage current increase in 4H-SiC Schottky power diodes are presented. Monte Carlo and TCAD simulations show that degradation is due to the synergy between applied bias and ion energy deposition. This degradation is possibly related to thermal spot annealing at the metal semiconductor interface. This thermal annealing leads to an inhomogeneity of the Schottky barrier that could be responsible for the increase leakage current as a function of fluence. [ABSTRACT FROM PUBLISHER]

A small degradation of threshold voltage and a significant reduction in dc and RF transconductance are observed for AlGaN/GaN high-electron-mobility transistors fabricated via three different process techniques and subjected to high voltage stress in the semi-ON bias condition. Low-frequency noise measurements as a function of temperature show peaks at ∼0.2, ∼0.5, ∼0.7, and/or ∼0.8 eV that increase with the magnitude and duration of high-field stress. The dehydrogenation of passivated Fe and O impurity defects and/or N antisite defects leads to increased charge trapping, noise, and transconductance degradation. Density functional theory calculations show that Ga vacancy motion and dehydrogenation of substitutional Fe complexes in the GaN buffer layer also contribute significantly to the poststress degradation of these devices. At higher stress voltages, these defects also likely contribute to device failure. [ABSTRACT FROM PUBLISHER]

Under heavy-ion exposure at sufficiently high reverse-bias voltages, silicon carbide (SiC) Schottky diodes are observed to exhibit gradual increases in leakage current with increasing ion fluence. Heavy-ion exposure alters the overall reverse current–voltage characteristics of these diodes, leaving the forward characteristics practically unchanged. This paper discusses the charge transport mechanisms in the heavy-ion damaged SiC Schottky diodes. A macro model, describing the reverse current–voltage characteristics in the degraded SiC Schottky diodes is proposed. [ABSTRACT FROM PUBLISHER]

We report the experimental data, quantum-mechanical calculations, and engineering-level modeling that provide insight into the atomic-scale processes that underlie the hot-electron degradation of AlGaN/GaN high-electron-mobility transistors during electrical stress at moderate drain bias. There is relatively large degradation (up to 20%) of the peak transconductance ( gm ) in the semi-ON state, along with a small shift of the threshold voltage ( VT ). The VT shift and gm degradation increase with temperature. A model of the degradation is presented, based on the hot-carrier-induced defect generation. The model considers carrier energy distributions for different temperatures obtained using an ensemble Monte Carlo (EMC) approach. The Ensemble Monte-Carlo results show that the concentration of energetic carriers is maximum at the end of the gate on the gate–drain access side in the semi-ON state of operation. The degradation is directly related to the number of carriers with sufficient energy to generate defects, and the carrier energy distribution depends strongly on the device temperature. The first-principles density functional theory calculations and the analysis suggest that the dehydrogenation of substitutional iron and its complexes is the dominant cause of the observed degradation in these devices. [ABSTRACT FROM AUTHOR]

The total ionizing dose response of Ge channel pFETs with raised Si0.55Ge0.45 source/drain is investigated under different radiation bias conditions. Threshold-voltage shifts and transconductance degradation are noticeable only for negative-bias (on state) irradiation, and are mainly due to negative bias-temperature instability (NBTI). Nonmonotonic leakage changes during irradiation are observed, which are attributed to the competition of radiation-induced field transistor leakage and S/D junction leakage. [ABSTRACT FROM PUBLISHER]

A probabilistic Bayesian modeling method for determining the effects of radiation-induced component-level parameter shifts on system-level performance is described. The modeling method incorporates information about the system design and component-level degradation into a Bayesian network and performs inference on the constructed network using Markov chain Monte Carlo approaches, producing distributions for the range of component responses. Deterministic simulations use the results of the Bayesian inference to determine the combined impact of multiple degraded components on system performance quantities. The goal of the modeling approach is to turn uncertain information into actionable knowledge. The utility of this approach is demonstrated using a case study based on total ionizing dose degradation of line-sensor components in a simple line-tracking robot system. [ABSTRACT FROM PUBLISHER]

The sensitivity of GaN/AlGaN HEMTs to 1.8 MeV proton irradiation is greatly enhanced by biasing the devices during irradiation and/or applying high field stress before irradiation. The resulting defect energy distributions are evaluated after irradiation and/or high field stress via low-frequency noise measurements. Significant increases are observed in acceptor densities for defects with \sim 0.2 and \sim 0.7 eV energy levels. These defects appear to dominate the degradation in threshold voltage and transconductance for these devices. Density functional theory (DFT) calculations show that N vacancy-related defects in GaN and hydrogenated ON complexes in AlGaN are strong candidates for the defects with \sim 0.2 eV energy levels in these devices. We also present evidence that the previously unidentified \sim 0.7 eV defect in GaN is a N anti-site defect (NGa). [ABSTRACT FROM PUBLISHER]

NPN and PNP bipolar junction transistors of varying sizes are irradiated with 4-MeV protons and 10-keV X-rays to determine the amount of ionization-related degradation caused by protons and calculate an improved estimate of displacement-related degradation due to protons. While different ratios of degradation produced by displacement damage and ionization effects will occur for different device technologies, this general approach, with suitable margin, can be used as a screen for sensitivity to neutron-induced displacement damage. Further calculations are performed to estimate the amount of degradation produced by 1-MeV equivalent neutron displacement damage compared to that produced by the displacement damage due to protons. The results are compared to previous work. [ABSTRACT FROM PUBLISHER]

The total-ionizing-dose robustness of low power microcontrollers is investigated. Experiments reveal that with increasing total ionizing dose (TID), the “Timing Window Violations,”i.e., inability of the instruction set to execute within the clock-cycle(s) lead to failures in microcontroller operations. Clock frequency and supply voltage of the microcontroller are varied to determine the maximum clock frequency at which the microcontroller can execute software subroutines without failure. Low power microcontrollers from two different manufacturers were tested. The maximum clock frequency decreases with increasing TID for both parts. A model for the degradation based on analysis of circuit level timing models is presented. The microcontroller robustness implications for system designers and ASIC designers are discussed. [ABSTRACT FROM PUBLISHER]

Electrical stress and 10-keV x-ray irradiation and annealing responses are evaluated for back-gate MoS2 transistors. Relative stability of device characteristics is observed for constant-voltage stress. The drain current decreases significantly after both positive and negative bias irradiation. Density functional theory calculations and ozone exposure experiments suggest that O atoms adsorbed on the MoS2 surface during 10-keV x-ray irradiation function as electron traps, causing mobility degradation and voltage shifts. [ABSTRACT FROM PUBLISHER]

AlGaN/GaN high electron mobility transistors (HEMTs) irradiated with 1.8-MeV protons show more relative degradation in RF power/current gain, cutoff frequency f_T, and maximum oscillation frequency fmax than DC transconductance. These result from radiation-induced increases in fast bulk and surface trap densities, as well as increasing impedance mismatch at high frequencies with increasing proton fluence. NH3-rich MBE devices show less degradation in DC transconductance, but more degradation in RF gain than Ga-rich devices. [ABSTRACT FROM PUBLISHER]

RRAM memory cells demonstrate resilience to ionizing dose and displacement damage, despite the presence of a nonhardened access transistor. Degradation in RRAM performance was not observed until large displacement damage doses and complete functionality was regained by cycling. A significant reduction in both the high and low resistance memory states and a complete collapse of the resistive window was observed for large proton fluences in RRAMs tested. Degradation in resistance states is associated with the generation of additional vacancies, which leads to (an) additional filament(s) in parallel to the existing conductive filament. Additional vacancies from displacement damage in the oxide of the resistive element do not permanently degrade device operation. The low resistance state is recovered to the pre-irradiation resistance through cycling at nominal high-speed switching conditions. Recovery of the resistive window to pre-irradiation values is obtained by applying longer write pulses which migrate remnants of radiation-induced filaments. [ABSTRACT FROM PUBLISHER]

The total ionizing dose response of both CMOS transistors and SiGe HBTs implemented without utilizing any radiation hardening by design techniques in Jazz Semiconductor's SBC-18-HXL BiCMOS technology platform is evaluated. The SiGe HBTs remain functional up to the 6 \Mrad(\SiO2) dose levels needed to support multi-Mrad exploration missions such as NASA's Europa mission. The CMOS devices are also functional to this extreme total dose. The nFETs exhibit significantly reduced shallow trench isolation leakage compared with nFETs implemented in prior SiGe BiCMOS processes. Both nFETs and pFETs show negligible transconductance and on-current degradation. We conclude that this SiGe process technology is a potential candidate for implementing reliable and survivable multi-Mrad total ionizing dose-hard electronic systems. [ABSTRACT FROM PUBLISHER]

The total-dose radiation tolerance of 32-nm nFETs is investigated. nFETs built in 32-nm RF-CMOS-on-SOI technology with high-k dielectrics show increased off-state leakage current and electron trapping in the gate oxide. The impact of CMOS-on-SOI technology scaling (from 65-nm to 32-nm) on the total-dose radiation tolerance and hot-carrier reliability (HCR) is investigated through both experiments and supporting TCAD simulations. The 32-nm nFETs exhibit less total-dose degradation compared to 45-nm nFETs. However, the hot-carrier degradation increases as the technology scales. An interplay of electric-field in the gate oxide and impact ionization in the channel region is responsible for the observed differences in the degradation mechanisms for the three technologies. [ABSTRACT FROM AUTHOR]

Monte Carlo analysis of hot-electron degradation in AlGaN/GaN high-electron mobility transistors shows that, for gate voltages corresponding to semi-ON bias conditions, the average electron energy has a spatial peak with \langleEAVE\rangle\sim1.5~\rm eV . The peak is located at the edge of the gate. At this location, the carrier versus energy distribution has a large tail extending over 3 eV. When transferred to the lattice, this energy can cause defect dehydrogenation and device degradation. These results are consistent with the experimental data indicating maximum degradation in the semi-ON bias condition. [ABSTRACT FROM AUTHOR]

Measurements of single particle displacement damage are presented as discrete increases in reverse-biased diode leakage current, or current steps, caused by individual heavy ions in ^252Cf-irradiated JFET diodes. The maximum size of measured current steps agrees with calculations obtained from the expression for Shockley-Read-Hall generation when the radiation-induced defect density is derived from Monte Carlo simulations of atomic displacements and the electric field enhancement of defect emission is taken into account. The distribution of the current steps shows good agreement with experimental data. [ABSTRACT FROM PUBLISHER]

The responses to 1.8 MeV proton irradiation of AlGaN/GaN HEMTs grown under Ga-rich and ammonia-rich conditions are investigated in this work. Changes in defect energy distributions of AlGaN/GaN HEMTs during proton irradiation are characterized via temperature-dependent low-frequency noise measurements. Density functional theory calculations show these changes are consistent with the reconfiguration and/or dehydrogenation of oxygen-related defects in Ga-rich devices. [ABSTRACT FROM PUBLISHER]

A model for radiation-induced interface-trap buildup distinguishes among the contributions of hydrogen dimerization, electron recombination, and electric field mechanisms, quantitatively explaining time-dependent and true dose rate effects in irradiated bipolar isolation oxides. Hydrogen dimerization is the dominant ELDRS mechanism for devices exposed to medium \ H2 concentrations (1% per volume), whereas \ H2 cracking dominates as \ H2 concentration is increased further. Electron recombination mechanisms contribute at high dose rates (> 100~\ rad(\ SiO2)/{\ {s}}), but are not the dominant ELDRS mechanism at dose rates lower than 100 \ rad(\ SiO2)/{\ {s}}). [ABSTRACT FROM AUTHOR]

The total ionizing dose response of triple-gate MOSFETs is investigated for various fin widths and bias conditions. Experiments and simulations are used to analyze the buildup of trapped charge in the buried oxide and its impact on the threshold-voltage shift and subthreshold-slope degradation. The higher total-dose tolerance of multiple-gate FinFETs with narrow fins is attributed to lateral gate control over the electrostatic potential in the body and especially at the Si fin/BOX interface. It is demonstrated that ON-state irradiation is the worst-case bias configuration for triple-gate MOSFETs through extensive experimental analysis. [ABSTRACT FROM PUBLISHER]

The switched dose rate technique has been proposed as an accelerated test technique for enhanced low-dose-rate sensitivity. The physical mechanisms at play when this technique is applied are investigated in this paper. The variation of Not and Nit is characterized using gated lateral pnp transistors to understand the kinetics of device degradation related to differences in mechanisms between high dose rate and low dose rate irradiations. [ABSTRACT FROM PUBLISHER]

The hot carrier and ionizing radiation responses of 45-nm SOI RF nMOSFETs are investigated. Devices with “tight” source/drain (S/D) contact spacing have improved RF performance but degraded hot carrier reliability and radiation tolerance. Devices with “loose” gate finger-to-gate finger spacing have improved RF performance and also improved hot carrier and radiation tolerance. The effects of finger width on the hot carrier stress and ionizing radiation degradation of strained silicon-on-insulator RF MOSFETs are also investigated. Enhanced degradation is observed for devices with wide finger widths and is attributed to the greater channel-region mechanical stress induced impact ionization. This result is contrary to the previous studies which showed that narrow channel width devices should exhibit greater damage. Taken together, these results have serious consequences for RF circuits that require large widths for sufficient RF gain. Finally, devices with symmetric halo doping are observed to exhibit greater total-dose degradation than devices with asymmetric halo doping. [ABSTRACT FROM PUBLISHER]

InAs–AlSb high-electron mobility transistors stressed with hot carriers may exhibit shifts in the peak transconductance toward more negative gate-voltages. The devices are most degradation prone in operating conditions with high longitudinal (in the direction of IDS) electric fields in the channel. Room-temperature annealing, gate current, and channel-mobility measurements suggest the presence of a metastable defect in the top AlSb layer. Device simulations and first-principles quantum–mechanical calculations are used to investigate the physical nature of the defects responsible for degradation. Metastable configurations of substitutional and interstitial oxygen have charge states and transition energies consistent with the degradation trends. [ABSTRACT FROM PUBLISHER]

The radiation response of advanced non-planar multiple gate field effect transistors (MuGFETs) has been shown to have a strong dependence on fin width (W). The incorporation of total ionizing dose (TID) effects into a physics-based surface-potential compact model allows for the effects of radiation-induced degradation in MuGFET devices to be modeled in circuit simulators, e.g., SPICE. A set of extracted parameters are used in conjunction with closed-form expressions for the surface potential, thereby enabling accurate modeling of the radiation-response and its dependence on W. Total ionizing dose (TID) experiments and two-dimensional (2D) TCAD simulations are used to validate the compact modeling approach presented in this paper. [ABSTRACT FROM AUTHOR]

The 1.8-MeV proton radiation responses are compared for AlGaN/GaN HEMTs grown under Ga-rich, N-rich, and NH3-rich conditions. The NH3-rich devices are more susceptible to proton irradiation than the Ga-rich and N-rich devices. The 1/ f noise of the devices increases with increasing fluence. Density functional theory calculations show that N vacancies and Ga-N divacancies lead to enhanced noise in these devices. [ABSTRACT FROM AUTHOR]

Abstract: Degradation of electronic devices by hot electrons is universally attributed to the generation of defects, but the mechanisms for defect generation and the specific nature of the pertinent defects are not known for most systems. Here we describe three recent case studies in III–V high-electron-mobility transistors that illustrate the power of combining density functional calculations and experimental data to identify the pertinent defects and associated degradation mechanisms. In all cases, benign pre-existing defects are either depassivated (irreversible degradation) or transformed to a metastable state (reversible degradation). [Copyright &y& Elsevier]