Enhancement-Mode Ga2O3 Vertical Transistors With Breakdown Voltage >1 kV

High-voltage vertical Ga ₂ O ₃ MISFETs are developed employing halide vapor phase epitaxial (HVPE) layers on bulk Ga ₂ O ₃ (001) substrates. The low charge concentration of ~10 ¹⁶ cm ^-3 in the n-drift region allows three terminal breakdown voltages to reach up to 1057 V without field plates. The devices operate in the enhancement mode (E-mode) with a threshold voltage of ~1.2-2.2 V, a current ON/OFF ratio of ~10 ⁸ , an ON resistance of ~13-18 mΩ·cm ² , and an output current of >300 A/cm ² . This is the first report of high-voltage vertical Ga ₂ O ₃ transistors with E-mode operation, a significant milestone toward realizing Ga ₂ O ₃ based power electronics.