Monolithic integrated quasi-normally-off gate driver and 600 V GaN-on-Si HEMT

Abstract

This work reports on a 600 V GaN-on-Si power transistor with monolithic integrated gate driver. The circuit is based on Schottky-gate depletion-mode technology and fabricated on a 2×3 mm2 chip. The push-pull gate driver stage implements a quasi-normally-off pull-up transistor, fabricated with monolithic integrated series-connected Schottky diodes for positive voltage-level shifting in the source path of a d-mode HEMT. The measured gate-source threshold voltage of the fabricated quasi-normally-off pull-up transistor is +2.7 V as compared to -2.9 V of the normally-on pull-down transistor. Pulsed-IV measurements determine an effective gate driver resistance of around 2 Ω. On-wafer measurements of the power transistor show low off-state leakage-currents up to 600 V blocking voltage with high wafer yield and 150 mΩ on-resistance. Finally, inductive-load switching measurements up to 450 V, 14.3 A show maximum switch node slew-rates during turn-on and turn-off transitions as high as 250 V/ns.