MOSFET

A type of FET (Field Effect Transistor). While a bipolar transistor controls output current using input current, an FET controls output current using input voltage. A MOSFET has a structure in which the gate electrode is separated from the semiconductor channel by a thin oxide insulating layer. Since it has a three-layer gate structure with metal (Metal), oxide (Oxid), and semiconductor (Semiconductor), it is called a MOSFET. Compared to junction FETs, MOSFETs are suitable for high-power and high-frequency applications. There are two types of MOSFETs: depletion type and enhancement type. In the depletion type, the drain current is maximum when the gate voltage is zero, and it decreases as voltage is applied in the reverse (negative) direction, eventually reaching an off state. Conversely, in the enhancement type, the drain current is minimal and in the off state when the gate voltage is zero, but increases as gate voltage is applied. Note that junction FETs only come in the depletion type.