Spacers with low dielectric constant have been significantly explored in the literature to reduce delay due to the parasitic capacitance. However, it substantially increases parasitic resistance due to Dielectric and Quantum Confinement based Dopant Deactivation (DQC-DD). In this letter, we have investigated the experimental signature of DQC-DD in the extension region of the FinFET and observed a significant reduction in the ON current due to it. Hence, it is essential to include DQC-DD into the simulation of FinFET, particularly those with narrow fin width, for the correct prediction of delay following the experiment.