Self-aligned SnO/ β -Ga 2 O 3 mesa heterojunction diodes with a PFOM of 0.93 GW/cm 2

In this article, a vertical SnO/ β -Ga 2 O 3 mesa heterojunction diode (mesa-HJD) fabricated through self-aligned etching is reported. The mesa structure eliminates the influence of lateral depletion at the region, leading to an improved breakdown characteristics in comparison with its unterminated heterojunction diode (UT-HJD) counterpart. The SnO/ β -Ga 2 O 3 mesa-HJD, featuring a 500 nm mesa depth, achieves a breakdown voltage (BV) of 1100 V, which can be improved to 1631 V by sidewall passivation. With the increase of mesa depth, BV increases, accompanied by the increase of specific on-resistance ( R on,sp ). Therefore, a maximum Baliga’s power figure of merit (PFOM) can be achieved for the optimized device with 500 nm mesa depth, giving the value of 0.93 GW/cm 2 for the passivated device. The mesa-HJD demonstrates considerable potential for application in high BV β -Ga 2 O 3 power electronic devices in the future.