SnO/β-Ga2O3 heterojunction barrier Schottky diodes for decreased reverse leakage current and improved breakdown voltage†

In this article, we report a vertical β-Ga₂O₃ heterojunction barrier Schottky (HJBS) diode fabricated by using reactive magnetron sputtering to selectively grow a circular p-type SnO film array. Compared to its Schottky barrier diode (SBD) counterpart, the HJBS diode shows a slightly increased turn-on voltage (V_on) and specific on-resistance (R_on,sp), but its breakdown voltage (BV) is greatly improved due to the decreased electric field crowding effect at the anode edge as well as the lateral surface depletion effect of the SnO/β-Ga₂O₃ p–n junction. A BV of 1375 V and a Baliga's power figure of merit (PFOM) of 0.37 GW cm⁻² achieved for the device with a spacing of 3 μm are expected to be improved by further shrinking the spacing. Meanwhile, the reverse leakage current (J_R) is lower than 2 μA cm⁻² (the detection limit of the system) even at a reverse bias (V_R) of 1250 V. The SnO/β-Ga₂O₃ HJBS diodes show great promise for use in future β-Ga₂O₃ power electronic devices with high PFOM, while maintaining a suppressed reverse leakage current.