Single- and double-heterostructure GaN-HEMTs devices for power switching applications

This paper reports on a detailed characterization of single- (SH) and double-heterostructure (DH) GaNbased HEMTs developed for the employment on power switching applications. DC, pulsed and breakdown characterizations have been performed in five different epitaxial structures. SH devices present higher ID current, however, DH devices present much lower leakage current and higher breakdown voltage, thanks to the better confinement provided by the back barrier layer. Kink effect have also been observed in these devices and the effect is enhanced in double heterostructure devices. Off-state stepstress, carried out on a sub-set of the available devices, revealed good reliability performances of DH devices. The limited reliability of the SH devices could be related to the punch-through leakage current. Correlation between current degradation and electroluminescence hot-spot in electroluminescence (EL) measurements has also been found.