We present a comparison between two-different approaches to including quantum effects in a Monte-Carlo simulator. The ability of our original Pearson Effective Potential (PEP) correction to correctly account for electrostatic quantum effects has been demonstrated on double-gate nMOS capacitors with different film thicknesses. In this work, results obtained from semi-classical, PEP corrected and multi-subband Monte-Carlo approaches are reported for a double-gate nMOSFET with a channel length L
= 20nm and a silicon film thickness T
= 8 nm at low and high drain voltages. For the first time, excellent agreements are obtained between quantum corrected and multi-subband Monte-Carlo methods on both electrical characteristics and microscopic quantities.