We introduce experimental results that reveal a small static and a slowly varying-dynamic magnetic field B induces a magneto-modulation of the gate leakage current of a 65 nm nMOSFET. For the case of a 100 mT (mili-Tesla) static B field a variation of the 6% (1.5 nA/27 nA) of the gate current is observed. For a 5 Hz slowly varying (±100 mT) square pulsed magnetic field, the gate current dynamic variation raises up to 18% (4.8 nA/27 nA). These experimental observations are explained in terms of space and time modulation of the two-dimensional surface inversion layer charge. The static B field dependent model is validated through Minimos-NT numerical simulations, while the dynamic B field experimental observations are reproduced with a SPICE macro-model, which uses the static device model as initial condition for the dynamic model. With this model we are able to predict the impact of small static and dynamic B fields on the gate leakage current and channel current interference of low-dimensional MOS transistors. We also propose this electro-magnetic experimental technique as an alternative for detailed exploration of the Si–SiO2 interface properties for 2 nm or thinner gate oxides, as well as for low-dimensional semiconductor devices.