Hot electron degradation effects in 0.14 mu m AlInAs/GaInAs/InP HEMTs

We report on hot electron stress measurements on 0.14 mu m MOCVD grown AlIA s/GaIn/InP HEMTs. The stress measurements increase the drain-source current and hence induce a temporary negative shift in the threshold voltage in un passivated HEMTs. A permanent negative shift in the threshold voltage has b een obtained in passivated HEMTs, The observed degradation (temporary/perma nent) is due to the storage of positive charges (created by the impact ioni zation in the channel) in the Schottky AlInAs layer (temporary) or at the i nterface of semiconductor-passivation layer (permanent). For a given drain- source bias, a shift in the threshold voltage is larger in the gate-source bias region where the device has a maximum transconductance value. (C) 1999 Elsevier Science Ltd. All rights reserved.