Correlation between permanent degradation of GaAs-based HEMT's and current DLTS spectra

This paper reports on the permanent degradation of the electrical characteristics of GaAs-based HEMT's following to hot-electron stressing. We demonstrate that the failure mechanism involved consists in the creation of deep levels either in the gate region or at the AlGaAs/GaAs interface in the access region between gate and drain. The nature of these deep levels has been analyzed by means of transconductance dispersion and drain current DLTS measurements. Transconductance and DLTS results are correlated here for the first time with hot-electron induced HEMT's degradation.