InAlN/AlN/GaN MIS-HEMTs With 10.8 \cdot Johnson Figure of Merit

• Published in: IEEE electron device letters Vol. 35; no. 5; pp. 527 - 529
• Main Authors: Downey, Brian P., Meyer, David J., Katzer, D. Scott, Roussos, Jason A., Ming Pan, Xiang Gao
• Format: Journal Article
• Language: English
• Published: IEEE 01.05.2014
• Subjects: Breakdown voltage; Current measurement; Gallium nitride; GaN; HEMTs; high-electron mobility transistors (HEMTs); III-V semiconductor materials; InAlN; Leakage currents; Logic gates; MODFETs; SiNx; high-electron mobility transistors (HEMTs); Breakdown voltage; InAlN; {\rm SiN}_{{\rm x}}; GaN
• ISSN: 0741-3106; 1558-0563
• DOI: 10.1109/LED.2014.2313023

A high combination of three-terminal breakdown voltage (VBK) and current gain cutoff frequency (f T ) was achieved with SiN x /InAlN/AlN/GaN metal-insulator- semiconductor high-electron mobility transistors (MIS-HEMTs). A 1-nm SiN x gate dielectric was deposited ex situ in a molecular beam epitaxy system and used to increase the carrier density of the 2-D electron gas under an ultrathin InAlN/AlN (2.3 nm/1 nm) barrier. Passivated MIS-HEMTs with a gate length of 80 nm exhibited a drain current density greater than 1.1 A/mm, a peak intrinsic transconductance g m,max of 800 mS/mm, and a maximum frequency of oscillation f max of 230 GHz. The combination of f T of 114 GHz and VBK of 95 V provides a Johnson figure of merit of 10.8 THz · V, which is among the highest reported values for fully passivated GaN HEMTs. A peak power-added efficiency of 37.5% with an output power of 1.25 W/mm and an associated gain of 9.7 dB was obtained by load-pull measurements at 40 GHz.