Beta-AlGaO/Ga2O3 Tri-Gate MOSHEMT with 70GHz fT and 55GHz fmax

TL;DR

This paper presents a high-frequency Beta-AlGaO/Ga2O3 tri-gate MOSHEMT with record fT and fmax, demonstrating its potential for advanced high-power RF applications.

Contribution

The paper reports the fabrication and characterization of the highest fT-L product Ga2O3 FETs to date, with a novel tri-gate structure and improved gate control.

Findings

fT=70 GHz and fmax=55 GHz achieved

fT-L product of 10.85 GHz-micron is the highest among Ga2O3 FETs

Devices exhibit high on/off ratio and stable operation under RF conditions

Abstract

We report Beta-AlGaO/Ga2O3 tri-gate heterostructure MOSHEMTs incorporating a thin 5 nm Al2O3 gate oxide layer for improved gate control and reduced leakage. The devices were fabricated on AlGaO/GaO heterostructures grown by ozone MBE on Fe-doped Ga2O3 (010) substrates. The tri-gate MOSHEMTs, with 1 micron-wide fins and Lg=155 nm, exhibit a peak current-gain cut-off frequency fT=70 GHz and a power-gain cut-off frequency fMAX=55 GHz.The fT.L product of 10.85 GHz-micron is the highest among reported Ga2O3 FETs to date. The devices show Vth =-0.5 V, an on/off ratio 10^6 I=80 mA/mm, a peak gm=60 mS/mm, and a low gate leakage current of 10^(-10) mA/mm at Vgs=0.5 V. Passivation with a 100 nm ALD Al2O3 layer effectively removes DC/RF dispersion and maintains stable operation under pulsed IV and repeated RF measurements. These results demonstrate the potential of tri-gate AlGaO/GaO MOSHEMTs for next-generation high-frequency and high-power applications.