The elemental base of semiconductor elements is constantly growing. Each new invention in this area, in fact, changes the whole idea of electronic systems. The circuitry capabilities in the design change, new devices based on them appear. Since the invention of the first transistor (1948), a lot of time has passed. The pnp and npn structures, bipolar transistors , were invented . Over time, an MIS transistor appeared, operating on the principle of changing the electrical conductivity of a surface semiconductor layer under the influence of an electric field. Hence another name for this element - field.
The very abbreviation MDP (metal-dielectric-semiconductor) characterizes the internal structure of this device. Indeed, his gate is isolated from the drain and source by a thin non-conductive layer. A modern MOS transistor has a gate length of 0.6 microns. Only an electromagnetic field can pass through it - this is what affects the electrical state of a semiconductor.
Let's look at how a field effect transistor works and find out what is its main difference from a bipolar “brother”. When the necessary potential appears, an electromagnetic field appears on its gate. It affects the resistance of the drain-source transition. Here are some of the benefits of using this appliance.
- In the open state, the drain-source transition resistance is very small, and the MOS transistor is successfully used as an electronic key. For example, it can control an operational amplifier by shunting a load or participate in logic circuits.
- Also of note is the high input impedance of the device. This parameter is quite relevant when working in low-current circuits.
- The low drain-to-source junction capacitance allows the use of an MOS transistor in high-frequency devices. In the process, there is no distortion in the transmission of the signal.
- The development of new technologies in the production of elements has led to the creation of IGBT transistors that combine the positive qualities of field and bipolar elements. Power modules based on them are widely used in soft starters and frequency converters.
When designing and working with these elements, it must be borne in mind that MOS transistors are very sensitive to overvoltage in the circuit and
static electricity. That is, the device may fail when touching the control pins. Use special grounding for mounting or dismounting.
The prospects for using this device are very good. Due to its unique properties, it has found wide application in various electronic equipment. An innovative direction in modern electronics is the use of power IGBT modules for working in various circuits, including induction ones.
The technology of their production is constantly being improved. Developments are underway to scale (decrease) the shutter length. This will improve the already good operating parameters of the device.