Beta-Ga2O3 Sub-Micron FinFETs with Si Delta-Doped Channel Modulating Charge Density Above 3x10^13 cm^-2

TL;DR

This paper demonstrates high-performance Beta-Ga2O3 FinFETs with Si delta-doped channels, achieving record charge density and promising high-frequency operation for RF and power electronics.

Contribution

It introduces a novel FinFET design with Si delta-doping in Beta-Ga2O3, achieving high charge density and improved RF performance.

Findings

Record high sheet charge density of 3.3x10^13 cm^-2

Peak drain current of 410 mA/mm and transconductance of 60 mS/mm

fT of 3.8 GHz and fMAX of 2.1 GHz for 0.8 μm gate length

Abstract

This letter reports on the design and demonstration of high-performance Beta-Ga2O3 FinFETs utilizing MOCVD-grown Si delta-doped channels to achieve enhanced carrier transport and electrostatic control. A record high sheet charge density of 3.3x10^13 cm^-2 was modulated using 100 nm fin channels, delivering a peak drain current of 410 mA/mm and a peak transconductance of 60 mS/mm. The FinFET architecture enables strong gate modulation, achieving a high Ion/Ioff ratio between 10^8 and 10^9. A low contact resistance of 0.42 ohm.mm was achieved to the Si delta-doped channel using MOCVD contact regrowth. Small-signal RF characterization revealed a current-gain cutoff frequency (fT) of 3.8 GHz and a maximum oscillation frequency (fMAX) of 2.1 GHz for a 0.8-micrometer gate length. These results demonstrate the efficacy of combining precision delta-doping with a 3D FinFET geometry for high-frequency Beta-Ga2O3 electronics, establishing a platform for future RF and high-power applications