Abstract
The drain current of the metal-oxide-semiconductor field effect transistors (MOSFETs) are controlled by the gate voltage. In some textbooks for universities and colleges the reason of the above characteristics is explained due to the change of the inversion layer thickness as “the current increases with the increase of the inversion layer thickness.” However this explanation is wrong. The right explanation why the drain currents are controlled by the gate voltage is that the total charge density induced in the inversion layer exponentially increase with the surface potential. In this paper why the explanation using the inversion layer thickness is wrong, and the right explanation is induced. In addition some examples of those wrong explanation are shown.
