A new analytical model to determine the drain-source series resistance of FOLD MOSFET

An analytical model to determine the intrinsic drain-source series resistance of a fully overlapped lightly doped drain (FOLD) MOSFET is presented. Considering outer and inner fringing capacitances and the depletion of the n(-) surface caused by the normal electric field from the gate, I-V characteristics, transconductance, drain conductance, channel resistance, cut-off frequency and transit time are studied. It is shown that, because of the lesser parasitic resistance of the FOLD structure, the device provides higher current driving ability than the lightly doped drain and can suppress hot carrier degradation by avoiding degradation due to the depletion of the n(-) region by electrons trapped in the sidewall. Some of the predictions of the model are verified with experimental data.