Temperature dependent characteristics of -Ga₂O₃ FinFETs by MacEtch

Understanding the thermal stability and degradation mechanism of beta-Ga2O3 metal-oxide-semiconductor field-effect transistors (MOSFETs) is crucial for their high-power electronics applications. This work examines the high temperature performance of the junctionless lateral beta-Ga2O3 FinFET grown on a native beta-Ga2O3 substrate, fabricated by metal-assisted chemical etching with Al2O3 gate oxide and Ti/Au gate metal. The thermal exposure effect on threshold voltage (Vth), subthreshold swing (SS), hysteresis, and specific on-resistance (Ron,sp), as a function of temperature up to 298 degrees C, is measured and analyzed. SS and Ron, sp increased with increasing temperatures, similar to the planar MOSFETs, while a more severe negative shift of Vth was observed for the high aspect-ratio FinFETs here. Despite employing a much thicker epilayer (similar to 2 lm) for the channel, the high temperature performance of Ion/Ioff ratios and SS of the FinFET in this work remains comparable to that of the planar beta-Ga2O3 MOSFETs reported using epilayers similar to 10-30x thinner. This work paves the way for further investigation into the stability and promise of beta-Ga2O3 FinFETs compared to their planar counterparts.