A 1100⁺V AlGaN/GaN-Based Planar Schottky Barrier Diode without Edge Termination

AlGaN/GaN-based planar Schottky barrier diodes with various spacings between ohmic and Schottky contacts are fabricated without any edge termination. The reverse leakage current of the devices quickly saturates at low reverse bias when the two-dimensional electron gas (2DEG) at the AlGaN/GaN interface is fully depleted. The corresponding breakdown voltage is found to follow a linear dependence on contact spacing and exceeds 1100 V at a contact spacing of 20 μm, yielding a high V_BR²/R_ON value of >280 MW⋅cm⁻². The observations are tentatively explained by a "natural super-junction" theory, in which ionized surface states at front surface of the AlGaN barrier have to be neutralized by reverse surface leakage current from the Schottky electrode.