Gallium oxide (Ga₂O₃) is promising next-generation semiconductor material for high power and low loss devices. Its wide band gap of 4.5-4.9 eV results in a high breakdown field of ~ 8 MV/cm and Baliga's FOM of ~ 3400. Among several polytypes of Ga₂O₃, β-Ga₂O₃ is the most viable option that can provide cost-effective and high-quality wafers with an edge-defined film-fed growth (EFG) method [1]. Several groups have reported excellent electric characteristics of vertical-type power devices using the β-Ga₂O₃ wafers [2]-[4]. We also demonstrated Schottky barrier diodes (SBDs) [5], trench metal-oxide-semiconductor SBDs (MOSSBDs) [6], junction barrier Schottky diodes [7], and trench metal-oxide-semiconductor field-effect transistors (MOSFETs) [8].