Single-event effects on ultra-low power CMOS circuits

Operating circuits in the subthreshold region is a simple method to lower total power consumption. The lower supply voltages decrease the electric fields present in the devices (resulting in lower charge collection), but increase the time required to remove the charge. These two competing mechanisms are characterized through two-photon absorption experiments for single-events to show that single-event vulnerability does not show a linear relationship with power supply voltage, as would be expected, in the subthreshold region. Single-event characterization is carried out using higher harmonic oscillation in ring oscillators with large numbers of stages over a wide range of supply voltages.