고전압 β-산화갈륨(β-Ga 2 O 3 ) 전력 MOSFETs

This report constitutes the first demonstration in Korea of single-crystal lateral gallium oxide (Ga2O3) as a metal-oxide-semiconductor field-effect-transistor (MOSFET), with a breakdown voltage in excess of 480 V. A Si-doped channel layer was grown on a Fe-doped semi-insulating β-Ga2O3 (010) substrate by molecular beam epitaxy. The single-crystal substrate was grown by the edge-defined film-fed growth method and wafered to a size of 10×15 mm2. Although we fabricated several types of power devices using the same process, we only report the characterization of a finger-type MOSFET with a gate length (Lg) of 2 μm and a gate-drain spacing (Lgd) of 5 μm. The MOSFET showed a favorable drain current modulation according to the gate voltage swing. A complete drain current pinch-off feature was also obtained for Vgs<-6 V, and the three-terminal off-state breakdown voltage was over 482 V in a Lgd＝5 μm device measured in Fluorinert ambient at Vgs＝-10 V. A low drain leakage current of 4.7 nA at the off-state led to a high on/off drain current ratio of approximately 5.3×105. These device characteristics indicate the promising potential of Ga2O3-based electrical devices for next-generation high-power device applications, such as electrical autonomous vehicles, railroads, photovoltaics, renewable energy, and industry.