The Impact of Etch Depth of D-mode AlGaN/GaN MIS-HEMTs on DC and AC Characteristics of 10 V Input Direct-Coupled FET Logic (DCFL) Inverters

Large input swing of logic circuits (> 10 V) are essential for the full utilization of GaN integrated circuits (ICs) to match drivers or protection circuits of mainstream Si and SiC power MOSFETs. A 10 V input DCFL inverter was successfully achieved using monolithic integration of E/D-mode GaN MIS-HEMTs, which can operate at high temperatures up to 250 °C. The impact of the threshold voltage of D-mode devices using different etch depths of AlGaN barrier on the DC and AC performance of DCFL inverters is systematically studied at various temperatures from 25 °C to 250 °C. These results present a large input swing and a straightforward design of GaN-based logic circuits using E-mode AlGaN/GaN MIS-HEMTs without additional drivers or level shifters, and propose a validate method to provide strong immunity to high voltage overshoot.