Velocity overshoot is a physical effect resulting in transit times for charge carriers between terminals that are smaller than the time required for emission of an optical phonon. The velocity therefore exceeds the

saturation velocity Saturation velocity is the maximum velocity a charge carrier in a semiconductor, generally an electron, attains in the presence of very high electric fields. When this happens, the semiconductor is said to be in a state of velocity saturation. Cha ...

up to three times, which leads to faster

field-effect transistor The field-effect transistor (FET) is a type of transistor that uses an electric field to control the flow of current in a semiconductor. FETs ( JFETs or MOSFETs) are devices with three terminals: ''source'', ''gate'', and ''drain''. FETs cont ...

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 bipolar t ...

switching. The effect is noticeable in the ordinary field-effect transistor for the gates shorter than 100 nm.

Ballistic collection transistor

The device intentionally designed to benefit from the velocity overshoot is called ballistic collection transistor (not to be mistaken with the

ballistic deflection transistor Ballistic deflection transistors (BDTs) are electronic devices, developed since 2006, for high-speed integrated circuits, which is a set of circuits bounded on semiconductor material. They use electromagnetic forces instead of a logic gate, a devi ...

References

Charge carriers {{CMP-stub

Ballistic collection transistor

See also

References