Temperature dependent characteristics of β-Ga₂O₃ FinFETs by MacEtch

Understanding the thermal stability and degradation mechanism of β-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 β-Ga₂O₃ FinFET grown on a native β-Ga₂O₃ substrate, fabricated by metal-assisted chemical etching with Al₂O₃ gate oxide and Ti/Au gate metal. The thermal exposure effect on threshold voltage (V_th), subthreshold swing (SS), hysteresis, and specific on-resistance (R_on,sp), as a function of temperature up to 298 °C, is measured and analyzed. SS and R_on,sp increased with increasing temperatures, similar to the planar MOSFETs, while a more severe negative shift of V_th was observed for the high aspect-ratio FinFETs here. Despite employing a much thicker epilayer (∼2 μm) for the channel, the high temperature performance of I_on/I_off ratios and SS of the FinFET in this work remains comparable to that of the planar β-Ga₂O₃ MOSFETs reported using epilayers ∼10-30× thinner. This work paves the way for further investigation into the stability and promise of β-Ga₂O₃ FinFETs compared to their planar counterparts.