Gate voltage and geometry dependence of the series resistance and of the carrier mobility in FinFET devices

In this work, we investigate the gate voltage and the geometry dependence of the series resistance and the carrier mobility in n-type and p-type FinFETs. A significant gate voltage dependence of the series resistance is observed, which is ascribed to the conduction modulation of the LDD region under the gate. The fin width dependence of the series resistance is investigated and two simple methods of normalization are compared. Mobility data in narrow (Wfin = 30 nm) and wide fin (Wfin = 3μm) have been compared. N-FinFETs show a higher mobility compared to the p-FinFET in both cases, but for narrow fins the difference is reduced since the mobility on the sidewalls improves for holes but degrades for electrons. We show that without taking into account the gate voltage dependence of the series resistance the mobility is significantly underestimated.