Alpha-Particle and Neutron-Induced Single-Event Transient Measurements in Subthreshold Circuits

Experimental data from alpha particle, neutron, and heavy ion testing are discussed and analyzed from a subthreshold voltage SET characterization circuit. Using a Schmitt trigger inverter target chain fabricated in a 28-nm bulk CMOS process, SET pulse widths are captured from an operating voltage down to 0.32 V. These results show that energetic particles can induce SET pulse widths that range up to hundreds of nanoseconds when operating at voltages well below the nominal voltage. Additionally, the results show that sub-Vt circuits are significantly more susceptible, as compared to circuits operating at nominal voltages, to low-energy particles inducing SETs that have a high probability of being latched as errors in a combinatorial logic design.