RECOVERY OF LOW-TEMPERATURE ELECTRON TRAPPING IN ALGAAS INGAAS PM-HEMTS DUE TO IMPACT-IONIZATION/

The de behavior of AlGaAs/InGaAs PM-HEMT's has been investigated at a low temperature. Two different failure modes have been identified acco rding to bias conditions, consisting of: a) a dramatic collapse in the drain current I-D, and b) a considerable shift in the threshold volta ge V-T. I-D decrease is due to trapping of electrons in deep levels in the gate-drain region, while trapping under the gate is responsible f or V-T shift. At high V-DS a recovery of the de devices characteristic s is observed, due to impact-ionization phenomena.