Ron Collapse, Breakdown and Degradation of d-mode MIS-HEMTs Based on GaN on Si Technology

The aim of this paper is to present an extensive investigation of the trapping and degradation mechanisms of GaN-based MIS-HEMTs grown on a 150 mm silicon substrate. The results of trapping investigation indicate that: (i) the analyzed devices may suffer from a dynamic Ron collapse and from a slight (dynamic) variation in threshold voltage, as emonstrated by pulsed ID-VD and ID-VG characterization; (ii) Ron collapse is due to the trapping of electrons in the gate-drain access region, as demonstrated by measurements carried out on samples with different gate-drain distances; (iii) Ron-transient investigation, carried out from the µs to the 100 s time scale, demonstrate the existence of one dominant deep level, with activation energy 1.03 ± 0.09 eV; (iv) this deep level is supposed to be located in the GaN or AlGaN epitaxial material (as discussed in the paper based on the comparison with previous literature reports), and to be responsible for both the dynamic Ron decrease and for the slight Vth shift measured during pulsed measurements.