  In this paper, we report enhanced breakdown characteristics of
Pt/BaTiO3/Al0.58Ga0.42N lateral heterojunction diodes compared to
Pt/Al0.58Ga0.42N Schottky diodes. BaTiO3, an extreme dielectric constant
material, has been used, in this study, as dielectric material under the anode
to significantly reduce the peak electric field at the anode edge of the
heterojunction diode such that the observed average breakdown field was higher
than 8 MV/cm, achieved for devices with anode to cathode spacing less than 0.2
microns. Control Schottky anode devices (Pt/Al0.58Ga0.42N) fabricated on the
same sample displayed an average breakdown field around 4 MV/cm for devices
with similar dimensions. While both breakdown fields are significantly higher
than those exhibited by incumbent technologies such as GaN-based devices,
BaTiO3 can enable more effective utilization of the higher breakdown fields
available in ultra-wide bandgap materials by proper electric field management.
This demonstration thus lays the groundwork needed to realize ultra-scaled
lateral devices with significantly improved breakdown characteristics.
