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.[1][2] The velocity therefore exceeds the saturation velocity up to three times, which leads to faster field-effect transistor or bipolar transistor switching. The effect is noticeable in the ordinary field-effect transistor for the gates shorter than 100 nm.[3]
^Chang, M F; Ishibashi, T (1996). Current Trends In Heterojunction Bipolar Transistors. World Scientific Publishing Co. Pte. pp. 126–129. ISBN978-981-02-2097-6.