MOSFET: principle of operation and scope

The study of the properties of a material such assemiconductor, allowed to make revolutionary discoveries. Over time, technologies have appeared that make it possible to manufacture diodes, MOS transistors, thyristors and other elements on an industrial scale. They successfully replaced electronic lamps and allowed to realize the most daring ideas. Semiconductor elements are used in all spheres of our life. They help us to process huge volumes of information, computers, tape recorders, TV sets, etc. are produced on their basis.

Since the invention of the first transistor, and thiswas in 1948, it's been a long time. There were varieties of this element: a point-like germanium, silicon, field or MOSFET. All of them are widely used in radio electronic equipment. The study of the properties of semiconductors does not stop in our time.

These studies led to the appearance of such alike a MOSFET. The principle of its operation is based on the fact that under the action of the electric field (hence another name - field field), the conductivity of the near-surface layer of the semiconductor located on the boundary with the dielectric varies. This property is used in electronic circuits for various purposes. MOSFET has such a structure that allows to reduce the resistance between the drain and the source under the action of the control signal to almost zero.

Its properties are different from the bipolar "competitor". They determine the scope of its application.

• High performance is provided byminiaturization of the crystal itself and its unique properties. This is due to certain difficulties in industrial production. At the present time, crystals with a gate of 0.06 μm are produced.
• A small transient capacitance allows these devices to operate in high-frequency circuits. For example, LSI with their use is successfully used in mobile communications.
• Virtually zero resistance, which hasMOSFET in the open state, allows you to use it as an electronic key. They can work in schemes for generating high-frequency signals or for shunting elements such as operational amplifiers.
• Powerful instruments of this kind are successfully used in power modules and can enter into induction circuits. A good example of their use may be a frequency converter.

When designing and working with such elementsit is necessary to take into account some features. MOSFETs are sensitive to reverse overvoltage and easily fail. In circuits with inductance, fast-acting Schottky diodes are commonly used to smooth out the reverse voltage pulse that occurs when switching.

Prospects for the use of these devices are sufficientlarge. Improving the technology of their manufacture goes along the path of crystal reduction (scaling of the shutter). Gradually, there are devices that are able to control more and more powerful electric motors.