Methods to determine the effective oxide thickness (EOT), fin height (Hfin) and fin doping concentration (Nfin) through gate to drain/source capacitance as a function of the front and the back gate voltage curves in triple-gate nMOS FinFET are presented. The proposed methods were validated through three-dimensional numerical simulations and experimental measurements showing that these methods can be also applied in triple-gate nMOS FinFET devices as a powerful tool for experimental validation.