Average transient current in SOI MOSFETs: a new technique for measuring the transient floating body effects

Several studies have demonstrated that floating body effects in partially-depleted SOI-CMOS technology can have a beneficial impact on the performance of digital circuits (Cristoloveanu and Li, 1995; Gautier et al., 1997). Nevertheless, the electrical characterization of transient phenomena is a difficult problem because the associated time constants can be close to a few nanoseconds. Direct measurement of the transient drain current (overshoot and undershoot) require a dedicated instrumental set-up (Jenkions et al., 1997) and do not correspond to the real conditions of IC operation (Wei et al., 1998). We propose an indirect method to measure the transient behavior of MOSFET drain current with a switching gate. The purpose of this work is to correlate the transistor time constants with the variation of the average drain current as a function of the switching frequency. The advantage of measuring the average current is to accurately reflect the transistor operation in logic circuits.