2D Amorphous GaOX Gate Dielectric for β-Ga2O3 Field-Effect Transistors

Appropriate gate dielectrics must be identified to fabricate metal–insulator–semiconductor field-effect transistors (MISFETs); however, this has been challenging for compound semiconductors owing to the absence of high-quality native oxides. This study uses the liquid-gallium squeezing technique to fabricate 2D amorphous gallium oxide (GaO X ) with a high dielectric constant, where its thickness is precisely controlled at the atomic scale (monolayer, ∼4.5 nm; bilayer, ∼8.5 nm). Beta-phase gallium oxide (β-Ga 2 O 3 ) with an ultrawide energy bandgap (4.5–4.9 eV) has emerged as a next-generation power semiconductor material and is presented here as the channel material. The 2D amorphous GaO X dielectric is combined with a β-Ga 2 O 3 conducting nanolayer, and the resulting β-Ga 2 O 3 MISFET is stable up to 250 °C. The 2D amorphous GaO X is oxygen-deficient, and a high-quality interface with…