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A radiation-hardened-by-design (RHBD) technique is described for reducing errors due to single-event effects at the floating input nodes of a switched-capacitor comparator. The technique is shown to significantly outperform the alternative 'brute force' design choice of increasing capacitor size. Index Terms--Comparator, radiation-hardened-by-design, RHBD, single-event, switched-capacitor circuits.

Frequency domain analysis is shown to be useful for quantifying the single-event vulnerability of a mixed-signal circuit. Frequency domain single-event analysis is demonstrated for different pipelined analog-to-digital converter topologies. Design tradeoffs of comparator redundancy are evaluated using a signal-to-noise ratio metric. Index Terms--Analog-to-digital converter (ADC), discrete Fourier transforms, pipeline, single-event.

Three-dimensional TCAD models are used in mixed-mode simulations to analyze the effectiveness of well contacts at mitigating parasitic PNP bipolar conduction due to a direct hit ion strike. 130 nm and 90 nm technology are simulated. Results show careful well contact design can improve mitigation. However, well contact effectiveness is seen to decrease from the 130 nm to the 90 nm simulations. Index Terms--Guard contacts, singe-event effects, technology computer-aided design (TCAD) modeling, parasitic bipolar conduction.

A novel mechanism for upset is seen in a commercially available 0.25 [micro]m 10-T SEE hardened SRAM cell. Unlike traditional multiple node charge collection in which diffusions near a single event strike collect the deposited carriers, this new mechanism involves direct drift-diffusion collection at an NFET transistor in conjunction with parasitic bipolar conduction in nearby PFET transistors. The charge collection with the parasitic bipolar conduction compromise the SEE hardened design, thus causing upsets. The mechanism was identified using laser testing and three-dimensional TCAD simulations. Index Terms--Charge sharing, parasitic bipolar, single event upset.

Heavy ion irradiation was simulated using a Geant4 based Monte-Carlo transport code. Electronic and nuclear physics were used to generate statistical profiles of charge deposition in the sensitive volume of an SEU hardened SRAM. Simulation results show that materials external to the sensitive volume can affect the experimentally measured cross-section curve. Index Terms--Cross section, Geant4, MRED, single event upset.