An assessment of RTN-induced threshold voltage jitter

Abstract

Power consumption is a key issue especially for the edge devices/units in an IoT system. Lowering operation voltage is an effective way to reduce power. As the overdrive voltage, Vg-Vth, becomes smaller, the device is more vulnerable to threshold voltage jitters. One source for the jitter is Random Telegraph Noises (RTN), which cause a fluctuation in both drain current, ΔId, and threshold voltage, ΔVth. Early works on RTN were focused on measuring ΔId and then evaluate ΔVth from ΔId/gm, where gm is transconductance. The accuracy of ΔVth obtained in this way is not known. The objective of this work is to assess its accuracy by comparing it with the ΔVth directly measured from pulse Id-Vg. It will be shown that the correlation between these two is poor, so that ΔVth must not be evaluated from ΔId/gm. This is caused by the device-specific localized current distribution near the threshold.