A VMOS () (vertical metal oxide semiconductor or V-groove MOS) transistor is a type of metal–oxide–semiconductor field-effect transistor (

MOSFET upright=1.3, Two power MOSFETs in amperes">A in the ''on'' state, dissipating up to about 100 watt">W and controlling a load of over 2000 W. A matchstick is pictured for scale. In electronics, the metal–oxide–semiconductor field- ...

). VMOS is also used to describe the V-groove shape vertically cut into the substrate material. The "V" shape of the

gate A gate or gateway is a point of entry to or from a space enclosed by walls. The word is derived from Proto-Germanic language, Proto-Germanic ''*gatan'', meaning an opening or passageway. Synonyms include yett (which comes from the same root w ...

allows the device to deliver a higher amount of

current Currents, Current or The Current may refer to: Science and technology * Current (fluid), the flow of a liquid or a gas ** Air current, a flow of air ** Ocean current, a current in the ocean *** Rip current, a kind of water current ** Current (hydr ...

from the source to the drain of the device. The shape of the

depletion region In semiconductor physics, the depletion region, also called depletion layer, depletion zone, junction region, space charge region, or space charge layer, is an insulating region within a conductive, doped semiconductor material where the mobil ...

creates a wider channel, allowing more current to flow through it. During operation in blocking mode, the highest electric field occurs at the N⁺/p⁺ junction. The presence of a sharp corner at the bottom of the groove enhances the electric field at the edge of the channel in the depletion region, thus reducing the breakdown voltage of the device. This electric field launches electrons into the gate oxide and consequently, the trapped electrons shift the threshold voltage of the MOSFET. For this reason, the V-groove architecture is no longer used in commercial devices. The device's use was a

power device A power semiconductor device is a semiconductor device used as a switch or rectifier in power electronics (for example in a switch-mode power supply). Such a device is also called a power device or, when used in an integrated circuit, a power IC. ...

until more suitable geometries, like the UMOS (or Trench-Gate MOS) were introduced in order to lower the maximum

electric field An electric field (sometimes called E-field) is a field (physics), physical field that surrounds electrically charged particles such as electrons. In classical electromagnetism, the electric field of a single charge (or group of charges) descri ...

at the top of the V shape and thus leading to higher maximum voltages than in case of the VMOS.

History

The

was invented at Bell Labs between 1955 and 1960. The V-groove construction was pioneered by

Jun-ichi Nishizawa was a Japanese engineer and inventor. He is known for his electronic inventions since the 1950s, including the PIN diode, static induction transistor, static induction thyristor, SIT/SITh. His inventions contributed to the development of ...

in 1969, initially for the

static induction transistor The static induction transistor (SIT) is a type of field-effect transistor (FET) capable of high-speed and high-power operation, with low distortion and low noise. It is a vertical structure device with short multichannel. The device was origina ...

(SIT), a type of junction

field-effect transistor The field-effect transistor (FET) is a type of transistor that uses an electric field to control the current through a semiconductor. It comes in two types: junction FET (JFET) and metal-oxide-semiconductor FET (MOSFET). FETs have three termi ...

(

JFET The junction field-effect transistor (JFET) is one of the simplest types of field-effect transistor. JFETs are three-terminal semiconductor devices that can be used as electronically controlled switches or resistors, or to build amplifiers. U ...

). The VMOS was invented by

Hitachi () is a Japanese Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1910 and headquartered in Chiyoda, Tokyo. The company is active in various industries, including digital systems, power and renewable ener ...

in 1969, when they introduced the first vertical

power MOSFET A power MOSFET is a specific type of metal–oxide–semiconductor field-effect transistor (MOSFET) designed to handle significant power levels. Compared to the other power semiconductor devices, such as an insulated-gate bipolar transistor (IG ...

in Japan. T. J. Rodgers, while he was a student at

Stanford University Leland Stanford Junior University, commonly referred to as Stanford University, is a Private university, private research university in Stanford, California, United States. It was founded in 1885 by railroad magnate Leland Stanford (the eighth ...

, filed a

US patent Under United States law, a patent is a right granted to the inventor of a (1) process, machine, article of manufacture, or composition of matter, (2) that is new, useful, and non-obvious. A patent is the right to exclude others, for a limit ...

for a VMOS in 1973.

Siliconix Siliconix Inc., later Temic Siliconix Inc. was a pioneering American semiconductor company known for its MOSFET designs. Now a subsidiary brand of Vishay, it was founded by Frances and Bill Hugle in 1962. History Siliconix was incorporated on ...

commercially introduced a VMOS in 1975. The VMOS later developed into what became known as the vertical DMOS (

VDMOS A power MOSFET is a specific type of metal–oxide–semiconductor field-effect transistor (MOSFET) designed to handle significant power levels. Compared to the other power semiconductor devices, such as an insulated-gate bipolar transistor (IG ...

). In 1978,

American Microsystems ON Semiconductor Corporation (stylized and doing business as onsemi) is an American semiconductor supplier company, based in Scottsdale, Arizona. Products include power and signal management, logic, discrete, and custom devices for automotive, c ...

(AMI) released the S2811. It was the first

integrated circuit An integrated circuit (IC), also known as a microchip or simply chip, is a set of electronic circuits, consisting of various electronic components (such as transistors, resistors, and capacitors) and their interconnections. These components a ...

chip specifically designed as a

digital signal processor A digital signal processor (DSP) is a specialized microprocessor chip, with its architecture optimized for the operational needs of digital signal processing. DSPs are fabricated on metal–oxide–semiconductor (MOS) integrated circuit chips. ...

(DSP), and was fabricated using VMOS, a technology that had previously not been mass-produced.

References

Transistor types MOSFETs Japanese inventions {{Technology-stub