Physics / mechanism
Gallium oxide (β-Ga₂O₃) is an ultrawide-bandgap (UWBG) semiconductor, Eg ≈ 4.8 eV, yielding a theoretical breakdown field ~8 MV/cm — roughly 4× GaN and 2× SiC. The critical figure of merit for power devices (Baliga’s FOM) sits an order of magnitude above SiC. Native substrates are grown via edge-defined film-fed growth (EFG) or Czochralski, now available at 4-inch (Flosfia, Novel Crystal Technology, Tamura). Doping is achieved n-type via Si or Ge; p-type remains problematic (no shallow acceptors), constraining bipolar designs. State-of-art MOSFETs and Schottky diodes demonstrate breakdown voltages >1 kV at on-resistances competitive with SiC theoretical limits. Thermal conductivity (~10–15 W/m·K) is the primary liability.
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