High-performance large-area β-Ga2O3 MIS trench Schottky barrier diodes with Al2O3/GaON interfacial insulators

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We demonstrate a large-area 1 × 2 mm2 β-Ga2O3 metal–insulator–semiconductor (MIS) trench Schottky barrier diode (SBD) designed with 60°-tilted fins and Al2O3/GaON interfacial double layers, achieving a low specific on-resistance (Ron,sp) of 7.3 mΩ cm2 and a high current/voltage of 10 A/670 V. We used a photoresist mask and BCl3-based inductively coupled plasma etching to realize 60°-tilted fin structures. Meanwhile, a high-activity atomic nitrogen beam was generated by a nitrogen atom source that irradiated the sidewalls of the fins to form an ultrathin GaON layer. The capacitance–voltage measurements reveal that the GaON layer inserted between Al2O3 and β-Ga2O3 reduced trap-related charging effects and expanded the depletion region. As a result, the density of interfacial traps was reduced by an order of magnitude from 2 × 1012 to 1.5 × 1011 eV−1 cm−2. Additionally, the ideality factor of the trench MIS SBD is 1.02, indicating a super high-quality interface at the metal/β-Ga2O3.