High-Performance HZO/InAlN/GaN MIS-HEMT with fT/fmax of 155/250 GHz

TL;DR

This paper demonstrates a Zr-doped HfO2 gated InAlN/GaN MIS-HEMT with record high fT/fmax of 155/250 GHz, showcasing its potential for millimeter-wave power applications.

Contribution

It introduces a novel HZO dielectric gate in InAlN/GaN HEMTs, achieving high-frequency performance surpassing previous devices.

Findings

fT of 155 GHz and fmax of 250 GHz achieved

High drain current and transconductance

Excellent on/off ratio and low DIBL

Abstract

Scaling of GaN high-electron-mobility transistors (HEMTs) usually increases gate leakage current and deteriorates breakdown characteristic, limiting the maximum drain current and output power density. These bottlenecks can be circumvented by inserting a dielectric material under the gate of HEMTs. Doped HfO2 is an excellent dielectric material but unexplored so far as the gate material of HEMTs for high-speed device application. Here we demonstrate that Zr-doped HfO2 (HZO)-gated InAlN/GaN metal-insulator-semiconductor (MIS) HEMTs exhibit remarkable properties. The device with a gate length (Lg) of 50 nm exhibits maximum drain current (Id,max) of 2.15 A/mm, a transconductance (gm) peak of 476 mS/mm, an on/off current ratio (Ion/Ioff) of 9.3*107, a low drain-induced barrier lowing (DIBL) of 45 mV/V. RF characterizations reveal a current gain cutoff frequency (fT) of 155 GHz and a maximum oscillation frequency (fmax) of 250 GHz, resulting in a (fT*fmax)1/2 of 197 GHz.These properties, particularly the high (fT/fmax)1/2 and JFOM are highly desirable for the millimeter-wave power applications, demonstrating the great technological potential of HZO/InAlN/GaN MIS-HEMTs.