What is MOS transistor?
The transistor of metal oxide oxide (MOS) is a building block of the most modern digital memories, processors and logical chips. It is also a common element in many integrated circuits of analog and mixed signals. These transistors are found in any number of electronic devices from mobile phones and computers to digitally inspected refrigerators and electronic medical equipment. MOS transistor is quite versatile and can act as a switch, amplifier or resistor. It is also known as a specific type of field effect transistor (FET) called isolated gate (IgFet) or MOS (MOSFET). Field effect refers to an electric field from the hub at the transistor gate.
MOS transistor is made on a semiconductor crystal substrate, usually made of silicon. The substrate ends with a thin insulating layer, often made of silicon oxide oxide. Above this layer is the gate, usually made of metal or polycrystalline silicon. Crystal area on one sideOna is called the source, while the second is a drain. Source and drain are generally "doped" with the same type of silicon; The channel below the gate is "doped" with the opposite type. This forms a structure similar to the standard transistor NPN or PNP.
MOS transistor is usually produced as PMOS or NMOS transistor. PMOS transistor has a source and drain made from silicon type P; The channel below the gate is type N. When a negative voltage is applied to the gate, the transistor switches. This allows the current current between the source and the drain. When the positive voltage is applied to the gate, it turns off.
The NMOS transistor is the opposite: the P -type channel with the N Source and drainage. When a negative voltage is applied at the NMOS transistor gate, it turns off; The positive tension turns on. One advantage that it nmosmi via PMOS switching speed - NMOS is generally faster.
Many integrated circuits use logical gates of additional MOS (CMOS). The CMOS gate consistsOf the two types of transistors connected together: one NMO and one PMOS. These gates are often preferred where energy consumption is critical. They usually do not use any energy until the transistors over interference from one to another.
MOSFET in depletion mode is a special type of MOS transistor that can be used as a resistor. Its area of the gate is made with another layer between the oxide insulator of silicon oxide and the substrate. The layer is "doped" with the same type of silicon as the area of drainage and sources. If there is no charge at the gate, this layer performs current. The resistance is determined by the transistor size when it is created. The presence of the charging gate turns off this type of MOS transistor.
Like most other transistors, the MOS transistor can amplify the signal. The amount of tokung current between the source and the drain changes with the gate signal. Some MOS transistors are designed and individually wrapped for mastering large currents. Can be used when switching power sources, highlyCapable amplifiers, coil controls and other analog or mixed signals. Most MOS transistors are used in low -power digital circuits. These are usually included inside chips with different parts, rather than standing separately.