Concept
MOSFET
Overview
In electronics, the metal–oxide–semiconductor field-effect transistor (MOSFET, MOS-FET, MOS FET, or MOS transistor) is a type of field-effect transistor (FET), most commonly fabricated by the controlled oxidation of silicon. It has an insulated gate, the voltage of which determines the conductivity of the device. This ability to change conductivity with the amount of applied voltage can be used for amplifying or switching electronic signals. The term metal–insulator–semiconductor field-effect transistor (MISFET) is almost synonymous with MOSFET. Another near-synonym is insulated-gate field-effect transistor (IGFET).
Physicist Julius Edgar Lilienfeld first proposed the concept of a field-effect transistor (FET) in 1925, but it was not possible to construct a working device at that time. The first working metal–oxide–semiconductor field-effect transistor (MOSFET) was invented in 1959 by engineers Mohamed Atalla and Dawon Kahng at Bell Labs. Their breakthrough—fabricating a practical field-effect transistor enabled by Atalla’s earlier work on silicon surface passivation and thermal oxidation—revolutionized electronics and paved the way for smaller and cheaper radios, calculators, computers, and other electronic devices.
The main advantage of a MOSFET is that it requires almost no input current to control the load current under steady-state or low-frequency conditions, especially compared to bipolar junction transistors (BJTs). However, at high frequencies or when switching rapidly, a MOSFET may require significant current to charge and discharge its gate capacitance. In an enhancement mode MOSFET, voltage applied to the gate terminal increases the conductivity of the device. In depletion mode transistors, voltage applied at the gate reduces the conductivity.
The "metal" in the name MOSFET is sometimes a misnomer, because the gate material can be a layer of polysilicon (polycrystalline silicon). Similarly, "oxide" in the name can also be a misnomer, as different dielectric materials are used with the aim of obtaining strong channels with smaller applied voltages.
The MOSFET is by far the most common transistor in digital circuits, as billions may be included in a memory chip or microprocessor. As MOSFETs can be made with either a p-type or n-type channel, complementary pairs of MOS transistors can be used to make switching circuits with very low power consumption, in the form of CMOS logic.
Overview adapted from Wikipedia (CC BY-SA 4.0; see the article history for authors).
Possible passages
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In what is termed osmose, we have a further mode of an allied kind. When on opposite sides of a permeable septum, and especially a septum of colloidal substance, are placed miscible solutions of different densities, a double transfer takes place: a large quantity of the less dense…
Herbert Spencer, The Principles of Biology, Volume 1
States what MOSFET is.
The discovery of radio-activity necessitated new views as to “atoms”. It was found that an atom of one radio-active element can break up into an atom of another element and an atom of helium, and that there is also another way in which it can change. It was found also that there can be different elements having the same place in the series; these are called “isotopes”. For example, when radium disintegrates it gives…
Bertrand Russell, Philosophy
States what MOSFET is.
Technical affairs give evidence that the work of inquiry, reporting and analysis is not always ineffectual. The development of a chain of "nation-wide" tobacco shops, of a well managed national telephone system, of the extension of the service of an electric-light plant testify to the fact that study, reflection and the formation of plans do in some instances determine a course of events. The effect is seen in both…
John Dewey, Human Nature and Conduct
States what MOSFET is.
Related ideas
- Integrated circuit
- Quantum mechanics
- Transistor
- Johns Hopkins University Press
- Transistor–transistor logic
- CMOS
- Wiley (publisher)
- Atom
- PMOS logic
- Field-effect transistor
- Bipolar junction transistor
- BiCMOS
Place in the tradition
Part of Logic gate.