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metal oxide semiconductor field effect transistor (MOSFET)

MOSFET, Metal Oxide Semiconductor Field Effect Transistor, describes a field effect transistor in MOS technology. With MOS technology, transistors can be manufactured whose control electrode is separated from the base material by a metal oxide layer and controls the current flow in the base material via electric fields. Due to the current separation of the base material and the control electrode, the gate, the control via the electric field is powerless.

The electrodes of a MOSFET are the source as the emitting electrode, the gate as the controlling electrode and the drain as the receiving electrode, which corresponds to the collector of a transistor. The MOSFETs developed in the 1960s were made of silicon or silicon dioxide, later, in the mid-1980s, the gate was made of polycrystalline silicon, polysilicon.

Structure of a MOSFET

Structure of a MOSFET

MOSFETs are characterized by extremely high impedances and low power consumption, which results in lower heat generation. Current is only drawn in the switching state; no current flows through the gates in the static state. The switching resistance is in the single- digit milli-ohm range. The switching times are about 10 ns.

Power MOSFET in SOT-6 package, photo: Fairchild

Power MOSFET in SOT-6 package, photo: Fairchild

The advantage of MOS technology, which is available in PMOS technology with P- channel FET as PFET and NMOS technology with N-channel FET as NFET, also lies in the wide supply voltage range, which can easily be several hundred volts. Due to the high impedance, these logics are particularly sensitive to static charges. All inputs and outputs should therefore not be operated potential-free.

MOSFETs are used in flaash memories, in processors, RAMs and ASICs. Also in power switches and as a voltage controlled transistor for current limiting.

The group of MOSFETs includes the Metal Semiconductor Field Effect Transistor( MESFET), the Metal Insulator Semiconductor Field Effect Transistor( MISFET), the Junction Field-Effect Transistor( JFET), the Super Junction MOSFET ( SJ-MOSFET), the Multiple Gate Field Effect Transistor( MuGFET) and the Isulated Gate FET ( IGFET).

Englisch: metal oxide semiconductor field effect transistor - MOSFET
Updated at: 27.11.2019
#Words: 318
Links: field effect transistor (FET), metal oxide semiconductor (Chip) (MOS), electrode, base material, layer
Translations: DE

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