Vertical Ga2O3 Schottky Barrier Diodes With Small-Angle Beveled Field Plates: A Baliga’s Figure-of-Merit of 0.6 GW/cm2

This letter demonstrates vertical Ga
₂
O
₃
Schottky barrier diodes (SBDs) with a novel edge termination, the small-angle beveled field plate (SABFP), fabricated on thinned
$\text{G}_{{2}}\text{O}_{{3}}$
substrates. Non-punch-though design is used for the drift region with a donor concentration of
${3}\sim {3.5} \times {10} ^{{16}}$
cm
⁻³
, rendering a device differential ON-resistance of
$\sim 2~\text{m}\Omega ~\cdot $
cm
²
. A new wet-etch technique is developed by using a bi-layer mask, which consists of spin-on-glass (SOG) and plasma-enhanced chemical vapor deposited (PECVD) SiO
₂
, to fabricate a very small bevel angle (∼ 1°) in the mesa and field plates. This SABFP structure facilitates the electric field spreading at device edges, rendering a breakdown voltage of 1100 V, a peak electric field of 3.5 MV/cm in Ga
₂
O
₃
at the Schottky contact edge, and an averaged electric field over 3.4 MV/cm underneath the contact. Our device demonstrates a Baliga’s figure of merit of 0.6 GW/cm
²
, which is among the highest in all reported Ga
₂
O
₃
power devices and comparable to the state-of-the-art GaN SBDs. These results show the great potential of Ga
₂
O
₃
SBDs for future power applications.