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Electrical stress and 10-keV X-ray irradiation and annealing responses are evaluated for carbon nanotube field effect transistors for nonvolatile memory applications. Less than 3% change in the drain current is observed during constant-voltage stress. Irradiation and annealing under positive gate bias induces more degradation in both drain current and memory window than under negative bias. Cycling of the on/off state leads to significant degradation in the memory window. [ABSTRACT FROM AUTHOR]

During future ITER maintenance operations, sensors and their embarked electronics will be exposed to a hostile and radioactive environment. This paper presents the design of a MGy radiation tolerant 16 bit resolver-to-digital converter (RDC) in 130 nm CMOS technology. The RDC features a Type II digital tracking loop, able to track resolvers with speeds up to 300 rps, and excitation frequencies up to 4 kHz. The RDC uses two integrated ΔΣ-analog-to-digital converters (ADCs) to digitize the resolver outputs. The 16 bit, 10 kHz ADCs utilize a correlated double sampling technique to remove radiation induced offset and 1/f-noise. The front-end features a static angular resolution of 16 bits (4.2 arcsec rms ) and a resolution of 10 bits (6 arcmin rms ) at a rotor speed of 100 rps. The circuit has a simulated radiation tolerance exceeding 1 MGy. It has the ability to operate under temperatures up to 125 °C, and to allow multiplexing with signals from other conventional sensors for compact, robust read-out architectures. [ABSTRACT FROM AUTHOR]

A comparison is made of the behavior of silicon on insulator buried oxides and wet thermal oxides before and after fluorine implantation and irradiation. Before irradiation, the electrical characteristics of the thermal oxide and buried oxide are significantly different. The fluorine implantation in the smart-cut ® buried oxide results in a large negative threshold shift due to the trapping of positive charges. These charges are associated with positively charged fluorine ions on implantation and are trapped at pre-existing trap sites, particularly at the bonding interface, and at additional defects caused by the ion implantation damage. This shift is absent in the wet thermal oxide. After Co 60 irradiation up to 500 Krad(Si), the negative flatband and threshold voltage shift in the fluorine implanted buried oxide is larger than in the unimplanted buried oxide indicating that any potential positive effect of fluorine on the passivation of interface states is more than offset by the additional trapping sites created during implantation. These results demonstrate that in the design of a transistor utmost care must be taken to prevent any fluorine being implanted into the buried oxide. [ABSTRACT FROM AUTHOR]

The total ionizing dose effect is experimentally investigated on the electrical characteristics of low on/off switching ratio TiO2 memristive memories for the first time. The ^60Co\ \gamma -ray irradiation reduces the dispersion of the I-V curves, the resistances and the switch voltages, but the degradations of parameters have no impact on the data storage and reading/writing operations, indicating great stability to the irradiation and potential to the space applications. Furthermore, the low on/off switching ratio devices are ideal samples for the investigations of radiation effect on the memristive devices due to their observable parameter variation post the irradiation exposure. [ABSTRACT FROM PUBLISHER]

Programmable Metallization Cells (PMC) are two- terminal elements that exhibit resistance switching based on the combination of bias dependent ion conduction through a solid-state electrolyte and reduction/oxidation (redox) reactions occurring at the electrode terminals. PMC based resistive random access memory (ReRAM) is currently used in emerging nonvolatile memory technologies and has the potential to be the successor of current flash memory. In this study we demonstrate the radiation tolerance of Ag-doped Ge40S60 based PMC elements that were irradiated up to a total ionizing dose (TID) of 10 Mrad(Ge40S60) using ^60Co gamma rays. The irradiation tests on the PMC devices, with two different Ag anode thicknesses (35 nm and 100 nm), show no significant degradation in the resistance switching characteristics. [ABSTRACT FROM PUBLISHER]

In this paper, we have studied the total ionizing dose (TID) radiation response up to 2 Mrad(Si) of silicon-oxide-nitride-oxide-silicon (SONOS) memory cells and memory circuits, fabricated in a 130 nm complimentary metal-oxide-semiconductor (CMOS) SONOS technology. We explored the threshold voltage ( V) degradation mechanism and found that the V shifts of SONOS cells depend on the charge state; simply programming the cell to a higher V cannot compensate for the radiation induced V loss. The off-state current ( I) increase in the SONOS cell is also studied in this paper. Both V and I degradation would affect the memory system. Read data failures are mainly caused by V shifts under irradiation, and program and erase failures are mainly caused by increased I, which overloads the charge pumping circuit. By varying the reference current, our 4 Mb NOR flash chip has the potential to survive a radiation dose of 1 Mrad(Si) in read mode. [ABSTRACT FROM AUTHOR]

Abstract: This paper presents a computational estimation of the total ionizing dose from protons and electrons in the Earth's magnetosphere and interplanetary space for a hypothetical CubeSat transiting from Earth to Mars. An initial hyperbolic escape of the spacecraft from Earth's gravitation is assumed, followed by an elliptical transfer from Earth to Mars under the Sun's gravitation. The rapid traversal of the Earth's radiation belt yields a smaller ionizing dose, whereas high-energy solar protons in the interplanetary space have the greatest effect on the ionizing dose during the transfer between the planets. Variation in the heliocentric distance of the spacecraft is considered in the calculation. Calculation of the shielding distributions with Geant4 and the transport of the ionizing particles across the obtained distributions yields an estimation of the total ionizing dose as a function of position within the spacecraft as well as statistical confidence levels. With a moderate confidence level, this calculation shows that a practical exploration of Mars with a CubeSat is possible in terms of the expected total ionizing dose. [Copyright &y& Elsevier]

The Topmetal-M is a newly designed monolithic silicon pixel sensor for charged particle tracking based on a novel detector structure and implemented in a new 130 nm High-Resistivity (> 1 k Ω cm) CMOS process. This sensor integrates the functionality of the Monolithic Active Pixel Sensor (MAPS) and the Topmetal sensor. It has a matrix of 512 × 400 pixels with the pitch of 40 μ m × 40 μ m. Heavy-ion campaigns with a 181 T a 35 + beam have been performed to study the performance of this Topmetal-M sensor. The test results demonstrate it has an excellent response to particle energy deposition. Furthermore,this sensor is still fully functional after exposure to ∼ 14.1 krad, and no Single Event Latch-up (SEL) occurred. In addition, the baseline, the Equivalent Noise Charge (ENC), and the number of bad pixels show relatively good performance. [ABSTRACT FROM AUTHOR]

The degradation of lateral double-diffused MOSFETs (LDMOS) due to total ionizing dose (TID) effects is examined in this paper using physics-based 2D TCAD simulations. The devices under test (DUTs) are built with a single reduced surface field (single-RESURF) structure and local oxidation of silicon (LOCOS) field oxide. The device structure was chosen for its topological simplicity in comparison to other modern LDMOS transistors to explore the impact of gamma radiation on small-AC and RF behavior. The results demonstrate fundamental differences between n-type (nLDMOS) and the p-type (pLDMOS) parameter shifts. Due to the distinct damage location in the pLDMOS, which is mainly the drift region, TID augments the values of the various parasitic capacitances. However, in the nLDMOS, TID reduced those values, especially the gate capacitance overshoot, as the degradation happens in the channel region and the bird's beak mostly. Consequently, the RF response and stability of the devices will differ. In addition, we present new research opportunities for TID effects on LDMOS transistors in particular, but also for radiation studies in general. • TCAD process simulation is conducted to get an accurate LDMOS transistor. • Mesh discretization of the final device to account for the various oxide thicknesses and doping regions. • Analytical calculation of the accumulated interface and bulk traps after radiation under a certain electric field. • Checking the accuracy of the simulation setup by extracting the threshold voltage shift. • Simulation of small-AC and RF behavior to see how TID affects various parasitic electric components. [ABSTRACT FROM AUTHOR]

In this work, the radiation responses of 0.25 μm bulk transistors irradiated up to 300 krad are discussed. The electricals characteristics shown are measured after irradiation at 95 K, 150 K, and 300 K. The transconductance improves significantly with total ionizing dose (TID) at low temperature and does not vary at room temperature. The impact of incomplete ionization of impurities introduced into the Lightly Doped Drain extensions is examined. Since the transconductance increase is more pronounced for the shortest transistors, positive charges trapped in spacer oxides are likely to constitute the source of this increase. The Technology Computer-Aided Design simulations help us to discuss the influence of charge build-up at the spacers' locations on the drain to source resistance. By the means of a resistivity analysis, the influence of LDD doping level and operating temperature on the TID response of devices is analyzed. Its potential evolution with technological integration is investigated. • The transconductance of bulk nMOSFETs increases after TID irradiation at cryogenic temperature. • This phenomenon is not observed at room temperature. • Through conductance measurements it is concluded that radiation-induced charges reduce the incomplete ionization of LDD. • Spacers and LDD regions must be carefully modeled to account for radiation effects, especially at cryogenic temperatures. [ABSTRACT FROM AUTHOR]

Abstract: The pseudo-MOS transistor is a quick and effective technique for characterizing the electrical properties of silicon-on-insulator (SOI) wafer. We investigated the total ionizing dose (TID) response of pseudo-MOS transistors fabricated on SOI wafers hardened by single or multiple step Si ion implantation. It is demonstrated that the two Si ion implantation methods can both improve the radiation hardness of SOI wafers owing to the generation of deep electron traps in the buried oxide (BOX). However, the lattice damage of top silicon film caused by the single step implantation compared with the multiple degenerates the electrical properties of transistors, especially for the sub-threshold swing. The high resolution transmission electron microscopy (HRTEM) was used to observe the lattice quality. [Copyright &y& Elsevier]

The effects of the radiation-induced trapped charge in shallow trench isolation (STI) and buried oxide (BOX) on total ionizing radiation response of 0.13 \mum partially-depleted silicon-on-insulator (PDSOI) NMOS technology are analyzed respectively. The positive trapped charge in the STI oxide, but not in the BOX, is responsible for the off-state leakage increase after ON bias radiation. A new method is proposed to calculate the surface charge density along the STI sidewall. This method takes into account the influences of the non-uniform electric field and the variable oxide thickness in the STI region. Moreover, the calculated non-uniform charge density along the STI sidewall is verified by three dimensional simulations. Even though there is charge-accumulation in the BOX, it shows minimal impact on the front-gate characteristics of the PDSOI devices in this 0.13 \mum technology, except for the device with low body doping concentration. The positive charge trapped in BOX can induce significant threshold voltage shift in the RVT (regular Vth) I/O NMOSFET through coupling effect. [ABSTRACT FROM PUBLISHER]

The radiation response of a multi-level cell (MLC) NAND flash is used to determine the organization of logical states as they correspond to floating gate charge levels of constituent bit cell transistors. This “logical decode” is then used to demonstrate how an MLC device can be used to emulate a single-level cell (SLC) flash with total dose radiation sensitivity equivalent to and even surpassing that of a comparable actual SLC device. In addition, it is shown that the logical decode must be taken into account when performing radiation testing on MLC flash devices so as to gather accurate worst case response data. [ABSTRACT FROM PUBLISHER]

Oscillation frequency of a high voltage ring oscillator is observed to change non-linearly with increasing dose. The change in oscillation is caused by buildup of oxide-trapped charge in both gate and isolation oxides post-radiation. A simulation methodology is described and implemented which successfully re-creates oscillator response by way of radiation-enabled simulation. Implementation of radiation-enabled simulation of ring oscillator is discussed. Simulation allows projection of oscillator response in-situ, allowing designers to anticipate changes in oscillation and implement radiation hardening as required. Alternatively, implementation of a ring oscillator as a reliability monitor in a large-scale circuit allows easily detectable observation of total dose effects on transistors. [ABSTRACT FROM PUBLISHER]

The effects of X-ray and proton radiation on a LiNbO_2 analog memristor are investigated by I-V hysteresis, Electrochemical Impedance Spectroscopy, low-frequency AC voltage, and X-ray diffraction analysis. Both electrical and structural characterization of an irradiated memristor show that irradiation leads to an increased level of defects in the LiNbO_2 crystalline lattice. These radiation-induced defects facilitate faster lithium movement as shown by electrochemical impedance spectroscopy measurements on the as-grown and irradiated memristor. X-ray radiation improves ionic motion in the bulk of the device and increases the ionic resistance at the LiNbO_2-metal interface. In the case of proton radiation, the memristance response improves due to an increase in ionic motion in the bulk and at the interfaces. It is also shown by Monte Carlo simulations that proton irradiation of LiNbO_2 results in structural damage, which was verified experimentally by an X-ray diffraction study. [ABSTRACT FROM PUBLISHER]

We measured the total ionizing dose response of gate-all-around silicon nanowire n- and pMOSFETs to x-ray doses up to 2Mrad(SiO2). We show that they are radiation hard, with no degradation in threshold voltage, off-state current, or subthreshold slope, even at the highest dose for a wide range of bias conditions. We attribute this to the intrinsically rad-hard feature of the gate-all-around device design, where the channel is no longer in contact with any insulating layers that could form a parasitic channel. [ABSTRACT FROM PUBLISHER]

The total ionizing dose response of triple-well FinFETs is investigated for various bias conditions. Experimental results show that irradiation with the transistor in the OFF state with the drain terminal high is the worst-case bias configuration. TCAD simulations are used to analyze the buildup of trapped charge in the trench isolation oxide and its impact on the increase in leakage current and subthreshold-slope degradation. The electric field distribution along the STI/fin boundary exerts a strong influence on the trapped charge in the isolation oxide, which induces a parasitic leakage current path at total ionizing doses of less than 200 krad(SiO2). [ABSTRACT FROM PUBLISHER]

This paper investigates total-ionizing dose effects on the electrical characteristics of HfO_2/Hf-based bipolar resistive-random-access-memory (RRAM) devices. 10-keV x-ray irradiation does not cause significant changes in resistance at levels up to 7 Mrad(SiO_2). Excess carriers generated by x-ray irradiation in the HfO_2 layer recombine or are trapped at defect sites in the HfO_2 layer or at interfaces between layers. They have no effect, however, on the conductive path of the RRAM devices. 1.8 MeV proton irradiation causes resistance degradation through simultaneous introduction of oxygen vacancies and displacement damage. TRIM simulations are used to explain the physical mechanisms of the radiation-induced damage. The devices are promising for radiation-hardened memory applications. [ABSTRACT FROM PUBLISHER]

We have performed time-domain reflectometry (TDR) measurements on nMOSFETs before and after irradiation on time scales relevant to MOS radio-frequency response. The decrease in effective impedance of MOSFETs with ionizing radiation exposure is greater for transistors biased in the off-state (all pins grounded) during TDR measurement than for transistors biased in the on-state (V_G high and the other terminals grounded). The increased admittance after irradiation is observable primarily in the off-state measurement. The increases in admittance (decreases in effective impedance) with TID correlate closely with decreases in trans-resistance at 0 V. These decreases result from increases in radiation-induced oxide-trap charge and interface-trap charge in the gate and/or shallow-trench isolation oxides. [ABSTRACT FROM PUBLISHER]

Programmable metallization cells (PMCs) are emerging ReRAM devices exhibiting resistance switching due to cation transport in a solid-state electrolyte and redox reactions at the electrodes. Their non-volatility and low power requirements have led to increased interest in their development for non-volatile memory applications. Investigation of the total dose response of PMCs will contribute to our understanding of radiation induced effects in these novel memory devices as well as assess their suitability for use in ionizing radiation environments. This work investigates the impact of total ionizing dose on the switching characteristic of silver doped Ge30{Se70} PMC memory devices. The results obtained show that the resistance switching characteristic of these cells which use a solid state electrolyte based on Ge30{Se70} is not affected by a total dose exposure of up to 10 Mrad(Ge30{Se70}). [ABSTRACT FROM PUBLISHER]

A new dosimeter for total ionizing dose that is based on a floating gate MOSFET is presented. The chip incorporates a reference standard MOSFET for temperature compensation and front-end electronics to provide manageable output signals. The floating gate is automatically recharged through an included charge pump circuitry, thus its operating range is spread without affecting the sensitivity. Two different sensitivity configurations are included in the same chip, so the dosimeter can be used under different radiation environments. An initial characterization has been carried out in order to evaluate its suitability for space missions. The results show that the proposed floating gate radiation dosimeter is adequate for space missions with levels of total ionizing dose up to at least 10 krad(Si). [ABSTRACT FROM PUBLISHER]

We have investigated the total ionizing dose (TID) radiation effects in AlGaN/GaN MOS-HEMTs as a function of dose and radiation bias, and compared them with conventional HEMTs. Under 10 keV X-ray irradiation, two distinct regimes of threshold voltage (Vth) shifts have been revealed: a rapid Vth shift at low doses [< 3krad (SiO2)] for both HEMTs and MOS-HEMTs, and an additional Vth shift only found in MOS-HEMTs for doses up to at least 2 Mrad (SiO2). The rapid Vth shift anneals quickly and is a strong function of layer material. We attribute this portion of the Vth shift to hole trapping in the AlGaN barrier layer. The Vth shift at high doses found only in MOS-HEMTs is attributed to hole trapping in the gate oxide. By comparing MOSFETs with HfO2 and Al2 O3 gate dielectrics that are annealed during processing at various temperatures, we find that 500^\circC annealed HfO2 shows the most promising TID response. [ABSTRACT FROM PUBLISHER]

Many Ge and III–V-based MOSFETs, as well as GaN-based MOS-HEMTs, are significantly compromised in performance and reliability by their high densities of interface, border, and oxide traps. Problems may also arise when characterizing traps in FETs made on high-mobility channels due to their device structures and material properties that are different from their conventional counterparts. In this paper, we present the results of our study of these traps as obtained by the use of several electrical characterization techniques. In particular, we will discuss the ac transconductance technique that we have recently proposed, which enables us to probe interface traps in the band gap and border and bulk traps in the gate dielectrics even without a body contact. We will also show that the inelastic electron tunneling spectroscopy offers the unique possibility to use electrical characterization to understand chemical origins of traps without using additional physical characterization techniques. Ionizing radiation-induced trapping of charges in MOSFETs and MOS-HEMTs made on III–V semiconductors is also reported and discussed. [ABSTRACT FROM PUBLISHER]

The Relativistic Proton Spectrometer (RPS) on the Radiation Belt Storm Probes spacecraft is a particle spectrometer designed to measure the flux, angular distribution, and energy spectrum of protons from ∼60 MeV to ∼2000 MeV. RPS will investigate decades-old questions about the inner Van Allen belt proton environment: a nearby region of space that is relatively unexplored because of the hazards of spacecraft operation there and the difficulties in obtaining accurate proton measurements in an intense penetrating background. RPS is designed to provide the accuracy needed to answer questions about the sources and losses of the inner belt protons and to obtain the measurements required for the next-generation models of trapped protons in the magnetosphere. In addition to detailed information for individual protons, RPS features count rates at a 1-second timescale, internal radiation dosimetry, and information about electrostatic discharge events on the RBSP spacecraft that together will provide new information about space environmental hazards in the Earth's magnetosphere. [ABSTRACT FROM AUTHOR]

Lasers and photodiodes for high luminosity large Hadron collider (HL-LHC) data transmission applications were irradiated with a 1-Gy dose of ^60\Co gammas. No change was observed in the performance of the lasers tested, and an order of magnitude increase in the leakage current of the InGaAs photodiodes was measured. [ABSTRACT FROM AUTHOR]

The total-ionizing-dose (TID) radiation tolerance of bandgap references in deep-submicron CMOS technology is generally limited by the radiation introduced leakage current in diodes. An analysis of this phenomenon is given in this paper, and a dynamic base leakage compensation (DBLC) technique is proposed to improve the radiation hardness of a bandgap reference built in a standard 0.13 \mum CMOS technology. A temperature coefficient of 15 ppm/^\circC from -40^\circC to 125^\circC is measured before irradiation. The voltage variation from 0^\circC to 100^\circC is only \pm1 mV for an output voltage of 600 mV. Gamma irradiation assessment proves that the bandgap reference is tolerant to a total ionizing dose of at least 4.5 MGy. The output reference voltage exhibits a variation of less than 3% during the entire experiment, when the chip is irradiated by gamma ray at a dose rate of 27 kGy/h. [ABSTRACT FROM AUTHOR]

A dummy gate-assisted n-type metal oxide semiconductor field effect transistor (DGA n-MOSFET) layout was evaluated to demonstrate its effectiveness at mitigating radiation-induced leakage currents in a conventional n-MOSFET. In the proposed DGA n-MOSFET layout, radiation-induced leakage currents are settled by isolating both the source and drain from the sidewall oxides using a p+ layer and dummy gates. Moreover, the dummy gates and dummy Metal-1 layers are expected to suppress the charge trapping in the sidewall oxides. The inherent structure of the DGA n-MOSFET supplements the drawbacks of the enclosed layout transistor, which is also proposed in order to improve radiation tolerance characteristics. The Vg-\rm Id simulation results of the DGA n-MOSFET layout demonstrated the effectiveness of eliminating such radiation-induced leakage current paths. Furthermore, the radiation exposure experimental results obtained with the fabricated DGA n-MOSFET layout also exhibited good performance with regard to the total ionizing dose tolerance. [ABSTRACT FROM PUBLISHER]

The temperature dependence of the low-frequency noise of 4H-silicon carbide (SiC) MOSFETs with nitrided oxides is reported over the temperature range 85–510 K. The 1/f noise decreases significantly with increasing measurement temperature. This decrease in noise results primarily from a decrease in the density of interface traps at increasing temperatures. The 1/f noise is also characterized after total ionizing dose irradiation and postirradiation annealing. No significant change in the 1/f noise is observed after the devices are irradiated to 1 Mrad (SiO2) and then annealed under bias at elevated temperature. These results show that the 1/f noise in 4H-SiC MOSFETs is dominated by the interaction of channel carriers with slow interface traps at temperatures <360~K and with border traps >\rm\!360~K. This result contrasts with most experience with Si/SiO2-based MOSFETs, and results from the wider bandgap and greater density of slow interface traps in SiC/SiO2-based MOSFETs than in Si/SiO2-based MOSFETs. [ABSTRACT FROM AUTHOR]

An overview is presented of total ionizing dose (TID) effects in MOS and bipolar devices from a historical perspective, focusing primarily on work presented at the annual IEEE Nuclear and Space Radiation Effects Conference (NSREC). From the founding of the IEEE NSREC in 1964 until \sim 1976, foundational work led to the discovery of TID effects in MOS devices, the characterization of basic charge transport and trapping processes in \SiO2, and the development of the first generations of metal-gate radiation-hardened MOS technologies. From \sim 1977 until \sim 1985, significant progress was made in the understanding of critical defects and impurities that limit the radiation response of MOS devices. These include O vacancies in \SiO2, dangling Si bonds at the \Si/SiO2 interface, and hydrogen. In addition, radiation-hardened Si-gate CMOS technologies were developed. From \sim 1986 until \sim 1997, a significant focus was placed on understanding postirradiation effects in MOS devices and implementing hardness assurance test methods to qualify devices for use in space systems. Enhanced low-dose-rate sensitivity (ELDRS) was discovered and investigated in linear bipolar devices and integrated circuits. From \sim 1998 until the present, an increasing focus has been placed on theoretical studies enabled by rapidly advancing computational capabilities, modeling and simulation, effects in ultra-thin oxides and alternative dielectrics to \SiO2, and in developing a comprehensive model of ELDRS. [ABSTRACT FROM PUBLISHER]

This document describes the radiation environments, physical mechanisms, and test philosophies that underpin radiation hardness assurance test methodologies. The natural space radiation environment is presented, including the contributions of both trapped and transient particles. The effects of shielding on radiation environments are briefly discussed. Laboratory radiation sources used to simulate radiation environments are covered, including how to choose appropriate sources to mimic environments of interest. The fundamental interactions of radiation with materials via direct and indirect ionization are summarized. Some general test considerations are covered, followed by in-depth discussions of physical mechanisms and issues for total dose and single-event effects testing. The purpose of this document is to describe why the test protocols we use are constructed the way they are. In other words, to answer the question: “Why do we test it that way?” [ABSTRACT FROM PUBLISHER]

Silicon-Germanium (SiGe) technology effectively merges the desirable attributes of conventional silicon-based CMOS manufacturing (high integration levels, at high yield and low cost) with the extreme levels of transistor performance attainable in classical III-V heterojunction bipolar transistors (HBTs). SiGe technology joins together on-die high-speed bandgap-engineered SiGe HBTs with conventional Si CMOS to form SiGe BiCMOS technology, including all the requisite RF passive elements and multi-level thick-Al metalization required for high-speed circuit design. Such an silicon-based integrated circuit technology platform presents designers with an ideal division of labor for realizing optimal solutions to many performance-constrained mixed-signal (analog + digital + RF) systems. The unique bandgap-engineered features of SiGe HBTs enable several key merits with respect to operation across a wide variety of so-called “extreme environments”, potentially with little or no process modification, ultimately providing compelling advantages at the circuit and system level, across a wide class of envisioned commercial and defense applications. Here we give an overview of this interesting field, focusing primarily on the intersection of SiGe HBTs, and circuits built from them, with radiation-intense environments such as space. [ABSTRACT FROM PUBLISHER]

The fifty year history of radiation effects in bipolar transistors at NSREC is summarized, covering neutron-induced displacement damage, total ionizing dose response (including enhanced low dose rate sensitivity, ELDRS) and single event effects. These phenomena, particularly TID and ELDRS in bipolar transistors, have received significant attention at NSREC. Several other radiation effects such as thermal mechanical shock, electrical overstress, prompt dose rate photoresponse and the response to neutral particle beams are not addressed. [ABSTRACT FROM PUBLISHER]

We have investigated total ionizing dose (TID) radiation effects in Al2O3-gated ultra-thin body In0.7Ga0.3 As MOSFETs. A non-monotonic dependence of the threshold voltage (Vth) on the X-ray radiation dose was observed and analyzed; the accompanying degradation in subthreshold swing (SS) likely is caused by non-uniform trapped charge in the near-interfacial Al2O3 rather than interface-trap generation. The off-current and gate breakdown voltage were independent of dose up to 6 Mrad(SiO2). Compared to the InP-free device, the device with an InP barrier is more vulnerable to TID effects in terms of Vth shift, SS, and mobility degradation. [ABSTRACT FROM PUBLISHER]

This paper deals with the effects of ^60Co gamma irradiation on punch-through commercial insulated gate bipolar transistors turn-off switching behavior. The response of the threshold voltage, the gate-emitter leakage current, the collector leakage current, the collector-emitter breakdown voltage and the turn-off switching parameters under three different in situ gate biases are described. Charge trapping in the gate oxide causes the decrease of the threshold voltage. It is shown that the decrease of this parameter and the modifications in the Miller plateau level and width result in an increase of the turn-off delay time, the collector current fall-time, the collector-emitter voltage rise-time, and consequently an increase of the turn-off switching losses and a decrease of the turn-off overshoot collector-emitter voltage. [ABSTRACT FROM AUTHOR]

We investigate total ionizing dose (TID) effects in graphene field effect transistors comprised of chemical vapor deposition grown graphene transferred onto trimethylsiloxy(TMS)-passivated SiO2Si substrates. TID exposure with a positive gate bias increases the concentration of positive oxide trapped charges near the SiO2/TMS/graphene interface making Coulomb-potential scatterer limited mobility more apparent. In particular, we observe asymmetric degradation in electron and hole mobility, the former degrading more rapidly. Consistent with the electron-hole puddle description, we observe an increase in intrinsic electron carrier density that varies linearly with the oxide trapped charge density, while the hole carrier density remains largely unaltered. These effects give rise to an increasing minimum conductivity. [ABSTRACT FROM AUTHOR]

Electrical stress and 10-keV x-ray and 1.8-MeV proton irradiation and annealing responses are evaluated for graphene-based non-volatile memory devices. The memory characteristics of these structures derive primarily from hysteretic charge exchange between the graphene and interface and border traps, similar to the operation of metal-nitride-oxide-semiconductor memory devices. Excellent stability and memory retention are observed for ionizing radiation exposure or constant-voltage stress. Cycling of the memory state leads to a significant reduction in memory window. [ABSTRACT FROM AUTHOR]

We study total dose effects in advanced multi- and single-level NAND Flash memories. We discuss retention and functional failures, analyzing the role of floating gate cells and peripheral circuitry, as compared to previous generations. We found that in these new devices, retention errors appear in all program levels. Guidelines on worst-case testing conditions are given. [ABSTRACT FROM AUTHOR]

We present a wideband, low noise amplifier (LNA) implemented in a Silicon-Germanium Heterojunction Bipolar Transistor (SiGe HBT) technology. This SiGe LNA covers a frequency range of 8–16 GHz and achieves a peak gain of 17.5 dB at nominal bias and a peak OIP3 of 15.8 dBm at 10 GHz at nominal bias. The noise figure (NF) of the LNA is 4.5–8.1 dB across band, and it nominally consumes 4 mA from a 4 V supply. Samples were irradiated with 63.3 MeV protons to proton-equivalent doses ranging from 200 krad(Si) to 2 Mrad(Si). This LNA incorporates bias control “tuning-knobs” to enable bias tuning to mitigate for RF performance loss due to total dose exposure and process variation in performance metrics. The effectiveness of the tuning “knobs” to compensate for lost post-irradiated performance was investigated. It was found that the LNA performance can be restored with the use of the tuning knobs with a performance tuning algorithm. [ABSTRACT FROM AUTHOR]

Solid state electrolytes fabricated with chalcogenide glass (ChG) are considered viable candidates for the next generation of non-volatile memory technologies. These glasses, which are composed of group IV and/or group V elements with those of group VI chalcogens (S, Se, and Te), are excellent metal ion conductors. Because of this property, the resistance across structures composed of ChG films sandwiched between active metal (e.g., Ag) and inert metal (e.g., Ni) electrodes can be switched upon the application of sufficient bias, thereby enabling memristive action. In this paper, the effects of ^60Co gamma-ray irradiations on Ag/Ge30Se70 test structures are investigated. The results show that exposure to high-energy photons can trigger the transport of Ag^+~ions from an active Ag top layer into an underlying Ge30Se70 ChG film. Post-irradiation annealing experiments also indicate that this “photo-doping” process is reversible once the radiation stress is removed. Numerical simulations which model the mechanisms of radiation-induced photo-doping and recovery are shown to agree well with the data. The results and analysis presented in this paper suggest the ChG-based memristors may be more susceptible to transient radiation effects than cumulative radiation damage. [ABSTRACT FROM AUTHOR]

This paper concerns bipolar transistors subject to a double aggression: dose irradiation and high-frequency interference. The electromagnetic interference is injected in a contactless way in the near-field zone around the device. Parameters of the interference are power and frequency, the latter largely out of band of operation of the transistors. The output voltage of the transistor exhibits changes, due to rectification and to some extent to current crowding. The importance of the base bias set-up for the type of change occurring in voltage is displayed. After irradiation with a ^60Co source, the voltage output will change under electromagnetic interference but sometimes in an opposite way as initially measured. The impact of the irradiation with respect to electromagnetic susceptibility is highlighted from a physical point of view. Finally preliminary results of simulation for susceptibility prediction are given and a discussion is given on the limits of the transistor model used. [ABSTRACT FROM AUTHOR]

Abstract: Computational results for the cumulative effect of ionizing radiation are presented for CubeSats taking into account the presence of trapped charged particles in the Earth''s magnetosphere, protons and heavy ions from the Sun, and the cosmic rays. In contrast to relatively larger satellites, CubeSats are often launched with minimal shielding structures. Therefore, detailed modeling of a CubeSat is performed based on currently available standard platforms. The geometrical modeling is then used for an estimation of the ionizing doses for various locations within the CubeSat spacecraft operating at low altitudes. The calculation is reiterated and extended for more exotic orbits, such as geostationary Earth orbits and lunar orbits, for the potential application of CubeSats in challenging space missions. [Copyright &y& Elsevier]

Resistive switching properties of valence change memory (VCM) resistive-random-access-memory (ReRAM) devices (TiN/HfO2/TiN) are investigated after exposure to proton radiation with total ionizing doses (TID) of 1.5, 3, and 5 Grad(Si) and compared to similar measurements from electrochemical metallization memory (ECM) ReRAM devices (Pt/HfO2:Cu/Cu). The TiN/HfO2/TiN ReRAMs show significantly superior TID radiation-hardness compared to Pt/HfO2:Cu/Cu ReRAMs: 1) All devices remained functional after radiation; 2) switching parameters including average Vset, Vreset, Ron, Roff showed minimal or no degradation; and 3) TID radiation enhanced the uniformity of resistive switching among all VCM devices. The superior radiation responses of the VCM ReRAM devices relative to ECM ReRAMs result from the distinct conduction filament (CF) formation mechanisms. For the VCM ReRAM system, the radiation-induced vacancy density does not serve to inhibit the trap-assisted tunneling associated with the Hf-rich CF formation kinetics. On the contrary, vacancy-promoted charge trapping promotes VCM CF stability. In strong contrast, proton-induced vacancies for the ECM ReRAMs inhibit the formation of the metallic filament through internal field reduction due to charge trapping. The comparison of TID effects suggests that HfO2-based VCM ReRAMs can be made radiation immune to a TID up to 5 Grad(Si) and may be highly suitable for rad-hard electronics applications. [ABSTRACT FROM PUBLISHER]

Irradiated Ge pMOSFETs have been characterized via charge pumping (ICP) and 1/f noise. The noise increases much more with irradiation than does ICP for devices with eight Si monolayers at the interface, while devices with five Si monolayers and lower halo implantation dose exhibit comparable increases in noise and ICP with irradiation. These results suggest that border traps in the HfO2 affect the noise more than interface traps, and that devices with eight Si monolayers have a higher border-trap density than devices with five Si monolayers. Noise measurements as a function of gate voltage show that the border trap density increases significantly toward the Ge valence band edge, while three-level charge pumping reveals an interface trap density that increases slightly toward midgap. [ABSTRACT FROM AUTHOR]

Space or military electronic components are subject to both electromagnetic fields and total ionizing dose. This paper deals with the electromagnetic susceptibility of a discrete low frequency transistor subject to total ionizing dose deposition. The electromagnetic susceptibility is investigated on both non-irradiated and irradiated transistors mounted in common emitter configuration. The change in susceptibility to 100 MHz–1.5 GHz interferences lights up a synergy effect between near field electromagnetic waves and total ionizing dose. Physical mechanisms leading to changes in signal output are detailed. [ABSTRACT FROM AUTHOR]

The space environment consists mainly of high-energy charged particles, such as protons, electrons and heavy ions. They are originating from several sources including galactic cosmic radiation, solar flares and van Allen belts. High energy electromagnetic radiation and neutrons have also been measured on spacecraft. Although shielding can reduce the effect of space radiation it cannot be eliminated completely. So the proper evaluation is the key to improve the system performance in space environment. In this paper, the space environment analysis and evaluation for high altitude satellites reported with an emphasis on radiation analysis as being the most significant source of space product failures. When there is no shielding, the forecasted value of Total Ionizing Dose (TID) is 109 rads (Si) and non-ionizing Displacement Damage Dose (DDD) is 1014 MeV/g (Si) for 18-year mission lifetime of high altitude satellites. Based on the analysis and evaluation results, it is determined that high altitude satellite components should not be less than ∼50 krad. [ABSTRACT FROM AUTHOR]

Abstract: Silicon ion implantation has been proved to be an effective method for total-dose hardening of SiO2 in MOS devices such as buried oxides in SOI devices, while the mechanisms are still in discussion. In this work, behavior of 10keV X-ray induced carriers in silicon implanted thermal SiO2 was investigated by comparing with Ar implanted SiO2. Photoluminescence (PL) spectroscopy and TRIM calculation were used to characterize the defects of the ion implanted SiO2 films. Metal–Oxide–Semiconductor (MOS) structures were fabricated for electrical characterization of the oxides. Positive or negative gate bias was applied during the irradiation to control the separation and transportation of radiation induced electrons and holes. Flatband voltage shifts and are extracted from high frequency capacitance–voltage (C–V) measurement results which are taken prior to and after certain total dose irradiation. The experiment result shows that both Ar and Si implantation and followed anneal could eliminate the net positive charge in SiO2 irradiated by X-ray. But different with Ar implanted oxide, in Si implanted oxide, the reduction of positive charge is highly dependent on the implanted Si ion fluence, and is well consistent with silicon nanoclusters evolvement tendency. From these results we conclude that along with increased electron trapping at the nanostructures which is suggested by previous studies, enhanced hole trapping and recombination caused by implantation induced vacancy defects are critical mechanism of reduced total ionizing dose effects on Si implanted oxides. [Copyright &y& Elsevier]