Record 94 GHz performance from N-polar GaN-on-Sapphire MIS-HEMTs: 5.8 W/mm and 38.5% PAE

Abstract

In this paper, we report on N-polar GaN-on-sapphire deep recess MIS-HEMTs with breakthrough performance at W-band. The devices show a high 8.8 dB linear gain at 94GHz at a 260mA/mm current density bias point, enabling excellent output power ($\text{P}_{\text{O}}$) density of 5.83 W/mm with record 38.5% power-added efficiency (PAE) at 14 V. Furthermore, at 12 V the device demonstrated even higher PAE of 40.2% with an associated 4.85 W/mm of output power density, a record. This power performance shows significant efficiency improvement over previous N-polar GaN-on-SiC, as well as Ga-polar devices and circuits, demonstrating the great potential of N-polar GaN-on-sapphire technology for mm-wave application with simultaneous high efficiency and power density.