Vertical Ga₂O₃ Schottky barrier diodes with guard ring formed by nitrogen-ion implantation

A guard ring (GR) was employed to improve the breakdown voltage (Vbr) of vertical Ga2O3 Schottky barrier diodes (SBDs) with or without a field-plate (FP) by eliminating electric field concentration at the edges of anode and FP electrodes. The GR structure was formed by nitrogen (N)-ion implantation. Four types of vertical SBD structures with: 1) neither a GR nor a FP; 2) a GR; 3) a FP; and 4) both a GR and a FP were fabricated on the same substrate. The SBDs with a GR [structures 2) and 4)] showed largerVbr values than their GR-free counterparts [structures 1) and 3)]. Considering the trade-off relationship between Vbr and specific on-resistance (Ron), a Vbr/Ron combination of 1.43 kV/4.7 m · cm2 for the GR/FP-SBD corresponds to one of the best balanced data for Ga2O3 SBDs.