Gate-lag effects in AlGaAs/GaAs power HFET's

Gate-lag effects have been characterized in as-fabricated and hot-carrier-s tressed power AlGaAs/GaAs HFET's and then compared with transconductance fr equency dispersion measurements and studied by means of numerical simulatio ns accounting for the occupation dynamics of surface deep-acceptor traps. W e have found a clear direct correlation between the amount of gate-lag and of transconductance dispersion. The gate-lag tam-off transients of increasi ngly degraded devices have been accurately simulated by suitably increasing the surface trap density. (C) 2001 Elsevier Science Ltd. All rights reserv ed.