Vertical Ga2O3 Schottky Barrier Diodes With Guard Ring Formed by Nitrogen-Ion Implantation

A guard ring (GR) was employed to improve the breakdown voltage (V
_br
) of vertical Ga
₂
O
₃
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 larger V
_br
values than their GR-free counterparts [structures 1) and 3)]. Considering the trade-off relationship between V
_br
and specific on-resistance (R
_on
), a V
_br
/R
_on
combination of 1.43 kV/4.7 mΩ · cm
²
for the GR/FP-SBD corresponds to one of the best balanced data for Ga
₂
O
₃
SBDs.