Gallium oxide (Ga2O3) metal-semiconductor field-effect transistors on single-crystal β-Ga2O3 (010) substrates

TLDR

The study demonstrates single‑crystal Ga₂O₃ MESFETs. Sn‑doped Ga₂O₃ was grown by MBE on β‑Ga₂O₃ (010) and used to fabricate circular MESFETs with 4 µm gate length and 20 µm source–drain spacing. The MESFETs exhibited ideal transistor behavior with full pinch‑off below –20 V, >250 V off‑state breakdown, 3 µA leakage, and a 10⁴ on/off ratio, underscoring Ga₂O₃’s promise for power applications.

Abstract

We report a demonstration of single-crystal gallium oxide (Ga2O3) metal-semiconductor field-effect transistors (MESFETs). A Sn-doped Ga2O3 layer was grown on a semi-insulating β-Ga2O3 (010) substrate by molecular-beam epitaxy. We fabricated a circular MESFET with a gate length of 4 μm and a source–drain spacing of 20 μm. The device showed an ideal transistor action represented by the drain current modulation due to the gate voltage (VGS) swing. A complete drain current pinch-off characteristic was also obtained for VGS < −20 V, and the three-terminal off-state breakdown voltage was over 250 V. A low drain leakage current of 3 μA at the off-state led to a high on/off drain current ratio of about 10 000. These device characteristics obtained at the early stage indicate the great potential of Ga2O3-based electrical devices for future power device applications.