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Total-ionizing-dose (TID) effects and low-frequency noise are evaluated in advanced bulk nMOS and pMOS FinFETs with SiO2/HfO2 gate dielectrics. Otherwise identical devices built with and without through-silicon via (TSV) integration exhibit threshold voltage shifts of less than 25 mV and changes in maximum transconductance of less than 1% up to 2 Mrad(SiO2). TSV integration negligibly impacts threshold shifts and degradation of subthreshold swing and $I_{\mathrm{\scriptscriptstyle ON}}/I_{\mathrm{\scriptscriptstyle OFF}}$ ratios. Similar low-frequency noise magnitudes and frequency dependencies are observed before and after TID irradiation for each device type. Effective densities of the near-interfacial electron traps responsible for the noise in the nMOS devices increase as the surface potential moves toward midgap, while effective densities of the hole traps that cause the noise in the pMOS devices increase as the surface potential moves toward the valence band edge.

The total-ionizing-dose (TID) response of indium gallium arsenide (InGaAs) MOSFETs with Al2O3 gate dielectrics and several channel lengths is evaluated under different biases. DC static characteristics show large negative threshold voltage $V_{\text {th}}$ shifts and subthreshold stretchout ( SS ), indicating net positive charge trapping in the gate oxide and generation of the interface and border traps. Hysteresis and $I_{d}$ – $V_{\text {gs}}$ measurements from cryogenic to high temperatures show the important role of defects in the Al2O3 gate dielectric to the TID response. Radiation-induced-hole trapping is attributed to oxygen vacancies in the Al2O3. The relatively large hysteresis in these devices is attributed primarily to dangling Al bonds in the near-interfacial Al2O3. Analysis of the temperature dependence of $V_{\text {th}}$ and SS suggests that the rate at which electrons leave the Al2O3 during a positive-to-negative gate-bias sweep is higher than the rate at which they enter during a negative-to-positive gate-bias sweep.

Total-ionizing-dose (TID) effects and low-frequency noise are evaluated in 30-nm gate-length bulk and silicon-on-insulator (SOI) FinFETs for devices with fin widths of 10–40 nm. Minimal threshold voltage shifts are observed at 2 Mrad(SiO2), but large increases in low-frequency noise are found, and significant changes in defect-energy distributions are inferred. Radiation-induced leakage current is enhanced for narrow- and short-channel bulk FinFETs. Short-channel SOI FinFETs show enhanced degradation compared with longer-channel devices. Narrow- and short-channel SOI devices exhibit high radiation tolerance. Significant random telegraph noise (RTN) is observed in smaller devices due to prominent individual defects.

We evaluate the total ionizing dose (TID) responses of InGaAs nMOS FinFETs with different gate lengths irradiated with 10-keV X-rays under different gate biases. The largest degradation after irradiation occurs at $V_{\mathrm {G}} = -1$ V. Radiation-induced trapped positive charge dominates the TID response of InGaAs FinFET transistors, consistent with previous results for InGaAs multifin capacitors. Shorter gate-length devices show larger radiation-induced charge trapping than longer gate-length devices, most likely due to the electrostatic effects of trapped charge in the surrounding SiO2 isolation and SiO2/Si3N4 spacer oxides. The 1/ $f$ noise measurements indicate a high trap density and a nonuniform defect-energy distribution, consistent with a strong variation of effective border-trap density with surface potential.

Proton radiation damage is an important failure mechanism for electronic devices in near-Earth orbits, deep space and high energy physics facilities. Protons can cause ionizing damage and atomic displacements, resulting in device degradation and malfunction. Shielding of electronics increases the weight and cost of the systems but does not eliminate destructive single events produced by energetic protons. Modern electronics based on semiconductors - even those specially designed for radiation hardness - remain highly susceptible to proton damage. Here we demonstrate that room temperature (RT) charge-density-wave (CDW) devices with quasi-two-dimensional (2D) 1T-TaS2 channels show remarkable immunity to bombardment with 1.8 MeV protons to a fluence of at least 10^14 H+cm^2. Current-voltage I-V characteristics of these 2D CDW devices do not change as a result of proton irradiation, in striking contrast to most conventional semiconductor devices or other 2D devices. Only negligible changes are found in the low-frequency noise spectra. The radiation immunity of these "all-metallic" CDW devices can be attributed to their two-terminal design, quasi-2D nature of the active channel, and high concentration of charge carriers in the utilized CDW phases. Such devices, capable of operating over a wide temperature range, can constitute a crucial segment of future electronics for space, particle accelerator and other radiation environments., 18 pages, 2 display items

Modern social intelligence includes the ability to watch videos and answer questions about social and theory-of-mind-related content, e.g., for a scene in Harry Potter, "Is the father really upset about the boys flying the car?" Social visual question answering (social VQA) is emerging as a valuable methodology for studying social reasoning in both humans (e.g., children with autism) and AI agents. However, this problem space spans enormous variations in both videos and questions. We discuss methods for creating and characterizing social VQA datasets, including 1) crowdsourcing versus in-house authoring, including sample comparisons of two new datasets that we created (TinySocial-Crowd and TinySocial-InHouse) and the previously existing Social-IQ dataset; 2) a new rubric for characterizing the difficulty and content of a given video; and 3) a new rubric for characterizing question types. We close by describing how having well-characterized social VQA datasets will enhance the explainability of AI agents and can also inform assessments and educational interventions for people., Comment: To appear in the Joint IEEE International Conference on Development and Learning and on Epigenetic Robotics (ICDL), 2020

GaN-channel based transistors are ideally suited for RF/5G applications and also provide the promise of monolithic integration on a conventional Si-platform. Due to the wide scope of high electron mobility GaN transistor architectures, their reliability assessment is essential to ensure their successful deployment in low-power applications such as mobile computing devices, as well as high-power applications such as autonomous vehicles and base stations. We identify the most important DCreliability metrics necessary for fair benchmarking of future GaNon-Si RF transistors. A detailed analysis of the shortlisted DCreliability parameters for three device types, namely MOSFETs, MOSHEMTs/MISHEMTs and HEMTs is presented. MOSHEMT/MISHEMT is identified as the most robust device architecture, due to the presence of a barrier layer alleviating the impact of certain degradation mechanisms. Defect distributions in the gate-stack of MOS devices are extracted using defect band modelling technique. MOSHEMT devices are shown to undergo negative and positive Bias Temperature Instability (BTI) under specific ranges of positive gate-overdrive, thereby demonstrating the importance of correctly estimating the oxide field for MOSHEMT devices. Degradation map methodology is partially developed to distinguish the different gate-oxide degradation mechanisms and model the device lifetime pertaining to each of the mechanisms.

Total-ionizing-dose mechanisms are investigated in 16-nm InGaAs FinFETs with an HfO2/Al2O3 gate-stack. Transistors are irradiated up to 500 krad(SiO2) and annealed at high temperatures. Irradiated devices show negative threshold-voltage Vth shifts, subthreshold stretch-out, and leakage current increases. These result from positive charge trapping in the gate oxide and shallow trench insulators, and increases in the interface and border-trap charge densities. Low-frequency noise measurements at different temperatures indicate a significant increase of noise magnitude in irradiated devices at an activation energy of ~0.4 eV. Density functional theory (DFT) calculations strongly suggest that transistor Vth shifts are due primarily to hole trapping at oxygen vacancies in HfO2, and the increased noise is due primarily to O vacancies in Al2O3. Additional contributions to the noise from defects in the GaAs buffer layer are also likely, primarily at low temperatures.

We report on Al(Ga,In)N HEMTs, MISHEMTs and MOSFETs integrated on 200 mm Si wafers using Au-free processing in standard Si CMOS tools, and discuss the performance tradeoffs, limitations and solutions. The main highlights of process optimization include low RF transmission loss (0.15 dB/mm at 20 GHz), state-of-the-art contact resistance (R C ) of 0.14 Ω mm for a non-Au, low thermal budget ( BD ) of >300 V (pre and post device processing). We show that MISHEMTs, which feature the highest field effect mobility (μ FE ), >2000 cm2/V.s, and the best 1/f noise performance, have the potential to outperform the other device types in terms of device scalability for high frequency operation.

Total-ionizing-dose effects on electrothermal micro- scanners are investigated using 10-keV X-rays and 14.3-MeV oxygen ions. The corresponding changes in mechanical displacement are measured using an optical microscope. Applied dc voltage and/or radiation-induced charging lead to changes in the vertical position and resistance of the structures. Radiation-induced changes in the vertical position and resistance and postirradiation recovery or superrecovery of these quantities are sensitive to dc biases applied during and/or after irradiation. Simple electrostatic and computational models are qualitatively consistent with observed trends in device response.

We have evaluated radiation-induced charge trapping and low-frequency noise in passivated black phosphorus (BP) MOSFETs with HfO2 gate dielectrics. Thinning the gate dielectric reduces total ionizing dose-induced threshold voltage shifts. The defect-energy distribution estimated from low-frequency noise measurements performed as a function of temperature decreases with increasing energy in as-processed devices. Local maxima in noise magnitude are observed in irradiated devices at activation energies of ~0.2 and ~0.5 eV. Larger defect-related peaks in noise magnitude in the range of 0.35–0.5 eV are observed after biased post-irradiation annealing, and/or vacuum storage of the devices after irradiation and annealing. Density functional theory calculations strongly support significant roles for O vacancies in HfO2 and H+ transport and reactions near the BP/HfO2 interface in the observed radiation response and low-frequency noise.

We use capacitance–frequency ( $C$ – $f$ ) measurements to provide lower bound estimates of border-trap densities in multifin MOS capacitors with high-K dielectrics built in Ge and InGaAs fin field effect transistor (FinFET) technologies before and after X-ray irradiation. The $C$ – $f$ method is illustrated for SiO2-based planar MOS capacitors and compared with high-frequency capacitance–voltage measurements. Lower effective border-trap densities are found before and after irradiation for multifin capacitors built in a strained Ge $p$ MOS FinFET technology than for similar devices built using an early-developmental stage InGaAs MOS technology. These results show the utility of $C$ – $f$ measurements in characterizing defect densities in MOS capacitors, particularly when large border-trap densities exist.

Nb2O5-based metal–insulator–metal (MIM) diodes are ideal for neuromorphic computing applications because they exhibit desirable rectification, hysteresis, and capacitance characteristics without electroforming. We employ capacitance-frequency measurements to evaluate the total-ionizing-dose res- ponse of these devices to avoid measurement-induced disturbance of trap distributions caused by typical gate-voltage sweeping methods. Power-law dependences are observed for the low-frequency capacitance and conductance, consistent with hopping conduction of carriers through the oxides. Despite their high oxygen-vacancy densities, the Nb2O5-based MIM diodes are radiation tolerant up to at least Mrad(SiO2) doses.

© 2019 Author(s). 1.8-MeV proton irradiation to a fluence of 10 14 /cm 2 does not significantly affect the resistance or low-frequency noise of copper or ruthenium resistors fabricated via modern microelectronic fabrication techniques used to form metal lines. The room-temperature noise of these Cu and Ru resistors is surprisingly similar to that of Cu and Pt metal lines and wires fabricated using late-1970s nanofabrication techniques; however, measurements of the temperature dependence of the noise show that the defect kinetics are quite different among the various materials. A large increase in the noise magnitude observed above 200 K in Cu but not in Ru is consistent with the superior resistance to electromigration that Ru lines have shown, relative to Cu. ispartof: Applied Physics Letters vol:114 issue:20 status: published