Effect of Multiple-Transistor Charge Collection on Single-Event Transient Pulse Widths

Heavy-ion data from a 130-nm bulk CMOS process shows a counterproductive result in using a common single-event charge collection mitigation technique. Guard bands, which are well contacts that surround individual transistors, can reduce single-event pulsewidths for normal strikes, but increase them for angled strikes. Calibrated 3-D TCAD mixed-mode modeling has identified a multiple-transistor charge collection mechanism that explains the experimental data, namely that angled strikes result in charge collection in the normally ON device that increases the restoring current on the struck device.