Abstract

In this paper we report on the hot-electrons in­duced degradation in AlGaAs/GaAs HEMT's and Al-GaAs/InGaAs/GaAs PM-HEMT's, consisting in a de­crease in the drain current. We have found that the amount of the degradation is correlated to to the impact-ionization in the channel, which is related to the electron energy. Creation of traps is the degradation mechanism which has been found to be responsible for the observed Id degradation. Drain current DLTS (Deep Level Tran­sient. Spectroscopy) analyses and transconductance fre­quency dispersion measurements have been used to iden­tify properties and localization of these traps. These techniques appear to be a powerful tool to study the relia­bility problems arising in HEMT structures due to defect created by hot electrons.