Realization of an n-channel GaAs/AlGaAs bistable field-effect transistor (BISFET)

The first realization of a novel heterostructure device, the bistable field-effect transistor (BISFET), is reported. The device uses an n-channel GaAs/AlGaAs inversion channel (IC) structure. It contains a positive feedback loop between the gate and source terminals, which is activated above a gate voltage of 1.7 V. This leads to abrupt transitions between high and low current states as the drain voltage is changed, with a switching ratio of 1.5. The transitions are accompanied by sharp changes in gate current as the feedback loop turns on and off. These transitions, referred to as switchup and switchdown, form a large hysteresis loop in the drain characteristics. Hysteresis as large as 3.7 V is observed, making the device strongly bistable.