What is a MOSFET? The definition of MOSFET and technical specs.


A MOSFET is a Field Effect Transistor and is a type of Metal Oxide Semiconductor Field Effect Transistor (MOSFET) that utilizes a metal oxide layer as the gate dielectric.

A MOSFET is an electronic device used for switching applications and amplifying electrical signals. It consists of three terminals called source, gate and drain. The operation of it is dependent on the flow of electric charge.

MOSFETs are available with both N-Channel and P-Channel configurations. The maximum current Rating for a single MOSFET ranges from 1 ampere to more than 10 amperes.

A MOSFET (metal-oxide-semiconductor field-effect transistor, pronounced “moss-fet”) is a transistor used for amplifying or switching electronic signals. Although the MOSFET is the most common transistor in both digital and analog circuits, the bipolar junction transistor was the transistor of choice early in the development of modern electronics, due to its lower manufacturing cost. The MOSFET was invented by Egyptian engineer Mohamed Atalla and Korean engineer Dawon Kahng at Bell Labs in November 1959. It is the basic building block of modern electronics, and the most frequently manufactured device in history, with an estimated total of 13 sextillion (1.3 × 1022) MOSFETs manufactured between 1960 and 2018.

The metal–oxide–semiconductor field-effect transistor (MOSFET) is by far the most widely used type of transistor and the most critical device component in modern integrated circuit (IC) chips. The larger the scale of a digitized system, such as a computer processor or memory chip, the more transistors it requires. What makes this remarkable is that all IC chips are built from only three types of components: resistors, capacitors, and transistors.

The MOSFET (metal-oxide-semiconductor field-effect transistor, or MOS transistor) is a major building block of modern electronic circuits, and the most frequently manufactured device in history. More than 10 billion MOSFETs are manufactured every year.

MOSFETs are three-terminal devices where the current flow between source and drain terminals is controlled by the voltage applied to a gate terminal. The operation of a MOSFET relies on the electrical properties of the oxide layer that separates a conducting channel from the gate electrode.

MOSFETs have many advantages over other types of transistors: they can be easily miniaturized, require little power to operate, and have high switching speed. They also have disadvantages that limit their use in some applications, such as digital logic circuits; for these applications bipolar junction transistors are often preferred.

A metal-oxide-semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET), also known as a metal-oxide-silicon transistor (MOS transistor, or MOS), is a type of insulated-gate field-effect transistor (IGFET), a device whose conductivity between its source and drain terminals is controlled by the voltage applied to its gate. The “metal” in the name MOSFET is sometimes a misnomer, because the gate material can be a layer of polysilicon (polycrystalline silicon).

The basic principle of the field-effect transistor was first patented by Julius Edgar Lilienfeld in 1925. Lilienfeld filed several additional patents in 1930 and 1931. In 1934 Oskar Heil patented an insulated-gate field-effect transistor (IGFET) with a solid gate and control electrode, but this was not put into production. In 1936 he patented a similar IGFET with a semiconductor gate electrode separated from the control electrode by an insulating layer, but this also was not produced.

In 1938 Herbert Mataré and Heinrich Welker filed a patent for a similar device, but it was not until after World War II

A metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, or MOS FET), also known as an insulated-gate field-effect transistor (IGFET), is a type of field-effect transistor (FET) that is fabricated by the controlled oxidation of a semiconductor, typically silicon. It has a covered gate, whose voltage determines the conductivity of the device. This technology is used for constructing integrated circuit (IC) chips, such as microprocessors, microcontrollers, memory chips and other digital logic circuits. The main advantage of the MOSFET is that it requires almost no input current to control the load current; when compared with bipolar junction transistors (BJTs), a MOSFET can be considered an “electronic switch”, which can be activated by applying a small voltage to its gate terminal. In an enhancement mode MOSFET, a positive gate-to-source voltage creates a conductive channel between the source and drain terminals, by attracting mobile electrons and “doping” the channel with n-type impurities.

A MOSFET is a type of field-effect transistor (FET) that is fabricated by the controlled oxidation of a semiconductor, typically silicon. This process creates a conducting channel within the oxide materials between source and drain regions of the device. By controlling voltage applied to the gate terminal, an electric field is created which controls current flow through the conducting channel.

A MOSFET can be used as either a switching device or as an amplifier. As a switch, it acts like an electrically operated valve with the entire channel acting as a valve seat to control current flow between source and drain terminals. As an amplifier, it will operate in either linear or saturation mode depending on gate bias conditions. In linear mode, output voltage is proportional to input voltage. In saturation mode, output voltage is independent of input voltage and gate current flow is regulated by gate bias conditions.

A MOSFET is a Field Effect Transistor that uses the field effect to control the shape and hence the conductivity of a “channel” between source and drain terminals. In enhancement mode MOSFETs, the channel does not exist until a voltage is applied to the gate. The width of the channel is then controlled by this gate voltage. This means that an enhancement mode MOSFET can be used as an electronically controllable switch, similar to a relay, but without any moving parts.

A depletion mode MOSFET has a channel present at all times. When there is no gate bias, this channel will be wide, and it can be made narrower by applying gate bias. This makes a depletion mode MOSFET act like a resistor with actively controlled resistance.


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