Extension of Universal Mobility Curve to Multi-Gate MOSFETs

The concept of "universal mobility" was successfully extended to multi-gate transistors. We developed a novel method to determine the effective electric field (E_eff) in multi-gate transistors experimentally taking all charges in and around the silicon body into account. By applying this method to double-gate (DG) transistors, we showed that E_eff goes from positive to negative, which depends on whether the front- or back- side channel is dominant. The validity of the universal relationship between mu_eff and E_eff was confirmed even with negative E_eff. Moreover, in the case of a symmetric DG transistor (V_fg=V_bg) like FinFETs, a high mu_eff can be obtained even at high gate-overdrive voltages because E_eff is always approximately zero.