First demonstration of robust tri-gateβ-Ga₂O₃nano-membrane field-effect transistors

Nano-membrane tri-gateβ-gallium oxide (β-Ga₂O₃) field-effect transistors (FETs) on SiO₂/Si substrate fabricated via exfoliation have been demonstrated for the first time. By employing electron beam lithography, the minimum-sized features can be defined with the footprint channel width of 50 nm. For high-quality interface betweenβ-Ga₂O₃and gate dielectric, atomic layer-deposited 15 nm thick aluminum oxide (Al₂O₃) was utilized with tri-methyl-aluminum (TMA) self-cleaning surface treatment. The fabricated devices demonstrate extremely low subthreshold slope (SS) of 61 mV dec^-1, high drain current (I_DS) ON/OFF ratio of 1.5 × 10⁹, and negligible transfer characteristic hysteresis. We also experimentally demonstrated robustness of these devices with current-voltage (I-V) characteristics measured at temperatures up to 400 °C.