ABSTRACT
The metal oxide semiconductor (MOS) transistor typically operates with very small currents, and for power electronics applications, thousands of MOS transistors are connected in parallel. There are MOS transistors, junction field effect transistors, static induction transistors, the punch-through transistors, and others. All of these devices employ the flow of majority carriers. The most popular one among this group is the MOS transistor, which is primarily used in integrated circuits. The MOS transistor can be considered a capacitor in which the applied voltage to the gate G would attract carriers from the semiconductor substrate. This layer of accumulated carriers near the surface conducts current between source and drain. There are a number of second-order effects that significantly affect the operation of a MOS transistor, such as channel-length modulation, carrier velocity limitation, surface mobility degradation, and subthreshold conduction. The major disadvantage of power MOS transistors is the relatively larger drain series resistance and much smaller transconductance in comparison to bipolar transistors.
