Hysteresis was observed with nonequilibrium characteristics in the sidegate
voltage dependence of drain current when measuring the threshold behavior
of sidegating effect in GaAs metal-semiconductor field-effect transistors i
n the voltage-controlled condition. Once the sidegate voltage is varied in
a quasi-steady state, hysteresis disappears immediately. A new mechanism is
presented to explain the phenomenon that hysteresis are related to electro
n capture and emission from EL2 deep center on the substrate side of channe
l-substrate junction. (C) 2000 American Institute of Physics. [S0021-8979(0
0)02001-6].