Single-Event Upset Responses of Metal-Oxide-Metal Capacitors and Diodes Used in Bulk 65nm CMOS Analog Circuits

The focus of this article is to characterize the behavior of metal–oxide–metal (MOM) capacitors when used in a switched-capacitor circuit in a standard 65-nm 1.2-V CMOS technology subject to ionizing radiation. The goal is twofold: first, to understand radiation-induced single-event effects on a fundamental building block of analog circuits unconstrained by a particular application and second, to explore the capacitor’s use as a particle detector analogous to the diode active-pixel sensor. The single-event signal response from the diode and MOM capacitor structures were consistent with ionization; the behavior of the diode was consistent with previously published results. The diode single-event signal response exhibited a step-like waveform, whereas the MOM capacitor exhibited an exponential-decay waveform, thus indicating different detection mechanisms where liberated charges were, respectively, either collected or not collected.