Non-quasi-static carrier dynamics of MOSFETs under low-voltage operation

We analyze the carrier dynamics in MOSFETs under low voltage operation for a 90 nm CMOS technology. For this purpose the displacement (charging/discharging) current, induced during switching operations is studied experimentally and theoretically. It is found that the experimental transient characteristics can only be well reproduced in the circuit simulation of low voltage applications by considering the carrier-transit delay in the compact MOSFET model. The switching frequency is found to decrease with reduced voltage due to diminished inversion condition and thus driving capability, which can be modeled with increased transit delay.