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Monte-Carlo radiation transport code is coupled with SPICE circuit level simulation to identify regions of single event upset vulnerability in an SEU hardened flip-flop, as well as predict single event upset cross sections and on-orbit soft error rates under static and dynamic operating conditions. Index Terms--Geant4, MRED, rate prediction, SEU, SPICE.

The presence of single event (SE) induced interconnect crosstalk has been measured and demonstrated experimentally using single and two photon laser absorption techniques in the IBM 90 nm CMOS9SF process. The dependency of SE interconnect crosstalk on the interconnect length and on the amount of deposited charge has been quantified through 3D mixed-mode simulations at this technology for two different supply voltages. Experimental and simulation results show this effect to increase the cross-section susceptible to SEs requiring careful design considerations to assure desired hardness levels. Index Terms--Complementary metal-oxide-semiconductor (CMOS), interconnect crosstalk, single event (SE), technology computer aided design (TCAD).

Heavy-ion testing of a Radiation-Hardened-By-Design (RHBD) 90 nm Dual Interlocked Cell (DICE latch) shows significant directional sensitivity results impacting observed cross-section and LET thresholds. 3-D TCAD simulations show this directional effect is due to charge sharing and parasitic bipolar effects due to n-well potential collapse. Index Terms--Charge sharing, cross-section, DICE latch, let threshold, n-well potential collapse, parasitic bipolar transistor, radiation hardened by design, single event circuit characterization, single event upset.

Charge sharing between adjacent devices can lead to increased Single Event Upset (SEU) vulnerability. Key parameters affecting charge sharing are examined, and relative collected charge at the hit node and adjacent nodes are quantified. Results show that for a twin-well CMOS process, PMOS charge sharing can be effectively mitigated with the use of contacted guard-ring, whereas a combination of contacted guard-ring, nodal separation, and interdigitation is required to mitigate the NMOS charge sharing effect for the technology studied. Index Terms--Charge sharing, guard-band, interdigitation, lateral parasitic bipolar, single event upset.

A three-dimensional (3D) technology computer-aided design (TCAD) model was used to simulate charge collection at multiple nodes. Guard contacts are shown to mitigate the charge collection and to more quickly restore the well potential, especially in PMOS devices. Mitigation of the shared charge collection in NMOS devices is accomplished through isolation of the P-wells using a triple-well option. These techniques have been partially validated through heavy-ion testing of three versions of flip-flop shift register chains. Index Terms--Guard contacts, single-event effects, technology computer-aided design (TCAD) modeling.

A CAD tool (SEUTool) is analyzed for simulating single-event upsets (SEUs) in large combinational logic circuits. SEUTool cross-section results show excellent agreement with experimental test data taken with the Boeing BDSP C30. Index Terms--Digital signal processing (DSP), modeling, SEUTool, single-event effects (SEEs), single-event upsets (SEUs), SPICE.

Total ionizing dose effects on fully-depleted (FD) silicon-on-insulator (SOI) transistors are studied when the devices are operated in single gate (SG) and double gate (DG) mode. The devices exhibit superiority in mobility and drain current when operated in DG mode compared to SG mode. Moreover, the dc characteristics of DG operated device are less vulnerable to total dose radiation induced damage. In particular, radiation-induced interface traps have less electrical effect in DG mode operation. Index Terms--Charge coupling, double gate, fully-depleted (FD) silicon-on-insulator (SOI) transistors, total dose effects.

We present spatial and temporal distributions of energy deposition in silicon obtained from Monte Carlo simulations with Geant4. Detailed simulations are performed for protons and alphas over a wide energy range and include contributions from discrete [delta]-rays and nuclear reactions. The simulation technique we employ produces physically realistic complex track structures for which the plausibility is evaluated by comparison to the linear energy transfer, radial dose, and temporal characteristics described in previous works. The variability of events, including the distribution of energy deposition at varying distances from the ion track is discussed. Finally, we examine the temporal evolution of extreme events to investigate the physicality of the common assumption that energy deposition can be considered instantaneous. Index Terms--Alphas, [delta]-rays, energy deposition, Geant4, ion track, metal oxide semiconductor (MOS), Monte Carlo simulation, protons, radial dose, radiation effects, single-event effects.

We examine the limits of performing single-event simulations using pre-averaged radiation events. Geant4 simulations show the necessity, for future devices, to supplement current methods with ensemble averaging of device-level responses to physically realistic radiation events. Initial Monte Carlo simulations have generated a significant number of extremal events in local energy deposition. These simulations strongly suggest that proton strikes of sufficient energy, even those that initiate purely electronic interactions, can initiate device response capable in principle of producing single event upset or microdose damage in highly scaled devices. Index Terms--Charge collection, extreme value statistics, Geant4, linear energy transfer, Monte Carlo simulation, protons, radiation effects, single-event effects, soft errors.

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]

Generally good agreement is obtained between the single-event output voltage transient waveforms obtained by exposing individual circuit elements of a bipolar comparator and operational amplifier to an ion microbeam, a pulsed laser beam, and circuit simulations using SPICE. The agreement is achieved by adjusting the amounts of charge deposited by the laser or injected in the SPICE simulations. The implications for radiation hardness assurance are discussed. Index Terms--Bipolar analog, comparators, laser beams, integrated circuit, ion beams, ion microbeams, ionization, operational amplifiers, radiation effects, single event transient, transient response.

Parasitic elements can play an important role in the single-event transient sensitivity of a circuit. This work describes how parasitics can affect the simulation response of linear circuits and shows how parasitics have been identified using a pulsed laser. Index Terms--Analog, spice, single-event, comparator, op-amp.

This work presents the development of a transistor-level circuit model of the LM124 operational amplifier specifically engineered and calibrated for analog single-event transient (ASET) computer simulations. The techniques presented rely heavily on datasheet specifications for electrical parameterization and experimental laser probing for dc and transient calibration. The resulting circuit model proves to be suitable for broad-beam SET predictions and fault diagnostics for space applications. Index Terms--Analog single-event transients, circuit modeling, electrical calibration, laser calibration, LM124 operational amplifier, transistor parameter extraction.

We have measured the 1/f-noise of 3 [micro]m x 16 [micro]m nMOS transistors with gate-oxide thickness of 48 nm as a function of frequency (f), gate voltage ([V.sub.g]), and temperature (T). For a temperature range of 85 K [less than or equal to] T [less than or equal to] 320 K, noise measurements were performed at frequencies of 0.3 Hz [less than or equal to] f [less than or equal to] 1 kHz with [V.sub.g] - [V.sub.th] = 2 V, where [V.sub.th] is the threshold voltage. Devices were operated in strong inversion in their linear regimes. A detailed comparison of the temperature and frequency dependences of the 1/f-noise of MOS transistors shows the importance of thermally activated charge exchange between the Si channel and defects in the oxide. After X-ray irradiation, the noise power increases after positive-bias irradiation and decreases after post-irradiation annealing, in agreement with previous work. For these devices and experimental conditions, detailed comparisons of the temperature dependencies of the noise magnitude and frequency dependence show that the 1/f-noise of nMOS transistors is very well described by the model of Dutta and Horn. As a result, we are able to extract the energy distributions before and after irradiation for the near-interfacial oxide (border) traps that cause the majority of the noise. Index Terms--1/f-noise, annealing, noise measurement, radiation effect, temperature dependence.

The experimental data presented in this paper indicate that the doping and geometry of critical transistors are the primary factors that affect the proton responses of the LM124 and LM148 operational amplifiers. The data also reveal that the electrical responses of these circuits and their input transistors to the combined effects of displacement damage and defects introduced by ionizing radiation are nonlinear. Analysis, supported by device simulation, shows that shifts in device parameters (surface potentials, carrier concentrations, etc.) caused by the buildup of oxide and interfacial defects affect the recombination rate due to traps resulting from displacement damage in the bulk silicon. This non-linearity complicates the analysis of proton radiation effects and can have a significant impact on the qualification of analog parts for use in space environments. Index Terms--Bipolar junction transistors, bulk lifetime, displacement damage, interface traps, ionization damage, NIEL, neutrons, operational amplifiers, oxide trapped charge, PFET, protons, surface recombination velocity, X-rays.