MOSFET

A type of FET (Field Effect Transistor). While a bipolar transistor controls the output current using input current, an FET controls the output current using input voltage. The MOSFET has a structure in which the gate electrode is separated from the semiconductor channel by a thin oxide insulating layer. It is called a MOSFET because it has a triple gate structure composed of Metal, Oxide, and Semiconductor. Compared to a junction-type FET, a MOSFET is suitable for applications requiring high output or high frequency. There are two types of MOSFETs: depletion type and enhancement type. In the depletion type, the drain current reaches its maximum when the gate voltage is zero and decreases as the voltage is applied in the reverse (negative) direction, eventually turning off. Conversely, in the enhancement type, the transistor is off and the drain current is minimal when the gate voltage is zero, but the drain current increases as the gate voltage is applied. Note that the junction-type FET only comes in the depletion type.