Surface effects on turn-off characteristics of AlGaAs/GaAs HFETs

The gate-lag turn-off transient of as-fabricated and hut-carrier stressed power AlGaAs/GaAs HFETs is addressed by quantitatively comparing experimental data with device simulations accounting for the occupation dynamics of surface deep-acceptor trays. Gate-lag waveforms of increasingly degraded devices can be accurately simulated by suitably increasing the surface trap density