Current conduction mechanisms through a Metal–Oxide–Semiconductor structure are characterized via Fowler–Nordheim (FN) plots. The extraction of the FN parameters like the electron/hole effective mass in oxide mox and in semiconductor msc, the barrier height at the semiconductor–oxide interface ϕB, and the correction oxide voltage Vcorr for a MOS structure is made using a vertical optimization process on the current density without any assumption about ϕB or mox. An excellent agreement is obtained between the FN plots calculated with the FN parameters extracted using a vertical optimization process with the experimental one.