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 Ga2O3 Schottky barrier diodes (SBDs) with a novel edge termination, the small-angle beveled field plate (SABFP), fabricated on thinned Ga2O3 substrates. Non-punch-though design is used for the drift region with a donor concentration of 3 similar to 3.5 x 10(16)cm(-3), rendering a device differential ON-resistance of similar to 2 m Omega . 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) SiO2, to fabricate a very small bevel angle (similar to 1 degrees) 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 Ga2O3 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 Ga2O3 power devices and comparable to the state-of-the-art GaN SBDs. These results show the great potential of Ga2O3 SBDs for future power applications.