The density and Hall mobility of free electrons in the channel of either dry- or wet-oxidized MOSFETs have been investigated by Hall effect. The wet-oxidized sample reveals a higher D-IT close to the conduction band edge than the dry-oxidized one, which leads to a reduction of the free electron density in the channel of the wet-oxidized MOSFET. The electron Hall mobility is nearly independent of the employed oxidation process. The observed change of the sign of the Hall coefficient RH at small gate voltages is attributed to an inhomogeneous distribution of the drain current.