Recovery of Low Temperature Electron Trapping in AlGaAs/InGaAs PM-HEMTs due to Impact-Ionization

Abstract

The dc behavior of AlGaAdnGaAs PM-HEMT’s has been investigated at a low temperature. Two different failure modes have been identified according to bias conditions, consisting of: a) a dramatic collapse in the drain current ID, and b) a considerable shift in the threshold voltage VT. ID decrease is due to trapping of electrons in deep levels in the gate-drain region, while trapping under the gate is responsible for VT shift. At high VQS a recovery of the dc devices characteristics is observed, due to impact-ionization phenomena