Integrated gate-protected HEMTs and mixed-signal functional blocks for GaN smart power ICs

On a GaN smart power IC platform, a robust GaN high electron mobility transistor (HEMT) with integrated gate protection is demonstrated by embedding a depletion-mode HEMT (D-HEMT) into the gate electrode of an enhancement-mode HEMT (E-HEMT). This protection scheme allows large input bias (e.g. 20 V) without gate-overdrive-induced reliability issues, and yields no penalties on the ON-state current and OFF-state breakdown voltage. Mixed-signal functional blocks, such as a 2-level quantizer circuit and a set/reset flip-flop, are demonstrated with operation up to 250°C to expand the design library for implementation of GaN smart power ICs.