High-field transport in GaAs transistors

Abstract
Resonant tunneling is used to explore the dynamics of electron transport in the electric field of reverse‐biased GaAs npn heterojunction bipolar transistor collectors. Extreme velocity overshoot is observed in a fraction of a percent of electrons which are accelerated ballistically in the Γ valley to energies greater than 1.5 eV. In addition, we show that Γ–X valley transfer is the dominant scattering mechanism for high‐energy Γ valley electrons.