MOS composite static induction thyristor (CSMT or MCS) is a combination of a MOS

transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch ...

connected in cascode relation to the SI-thyristor. The SI thyristor (SITh) unit has a gate to which a source of MOS transistor is connected through a voltage regulation element. The low conduction loss and rugged structure MCS make it more favorable than conversional IGBT transistors. In the blocking state nearly the complete voltage drops at the SITh. Thus the MOSFET is not exposed to high field stress. For fast switching the MOSFET with only 30–50 V blocking voltage is able. In IGBT,

charge carrier In physics, a charge carrier is a particle or quasiparticle that is free to move, carrying an electric charge, especially the particles that carry electric charges in electrical conductors. Examples are electrons, ions and holes. The term is u ...

concentration at emitter side in n-base layer is low as

hole A hole is an opening in or through a particular medium, usually a solid body. Holes occur through natural and artificial processes, and may be useful for various purposes, or may represent a problem needing to be addressed in many fields of en ...

s injected from collector easily pass to emitter electrode through p-base layer. Thus the wide-base pnp transistor operates by virtue of its current

gain Gain or GAIN may refer to: Science and technology * Gain (electronics), an electronics and signal processing term * Antenna gain * Gain (laser), the amplification involved in laser emission * Gain (projection screens) * Information gain in d ...

characteristics causing the rise collector-emitter saturation voltage. In an MCS the positive difference between the voltage of regulation element and conduction voltage drop of MOSFET is applied to location between the collector region and emitter region of the pnp transistor. Hole concentration is accumulated at emitter side in n-base layer because of impossibility of the hole flow through forward bias collector-base junction of the pnp transistor. Carrier distribution in n-base is similar to that of saturation

bipolar transistor A bipolar junction transistor (BJT) is a type of transistor that uses both electrons and electron holes as charge carriers. In contrast, a unipolar transistor, such as a field-effect transistor, uses only one kind of charge carrier. A bipola ...

and low saturation voltage of MCS, even at high voltage ratings, can be achieved.

References

{{Reflist Solid state switches Semiconductor devices