Current Aperture Vertical $\beta$ -Ga2O3 MOSFETs Fabricated by N- and Si-Ion Implantation Doping

Depletion-mode vertical Ga
₂
O
₃
metal-oxide-semiconductor field-effect transistors featuring a current aperture were developed on a halide vapor phase epitaxial drift layer grown on a bulk β-Ga
₂
O
₃
(001) substrate. Three ion implantation steps were employed to fabricate the n
⁺⁺
source regions, lateral n channel, and p current blocking layers, where Si and N were selected as the donor and deep acceptor dopant species, respectively. The transistors delivered a drain current density of 0.42 kA/cm
²
, a specific on-resistance of 31.5 mΩ·cm
²
, and an output current on/off ratio of over 10
⁸
. High-voltage performance of the present devices was hampered by a large gate oxide field in the off-state causing high gate leakage, a limitation that can be readily overcome through optimized doping schemes and an improved gate dielectric. The demonstration of a planar-gate vertical Ga
₂
O
₃
transistor based on a highly manufacturable all-ion-implanted process greatly enhances the prospects for Ga
₂
O
₃
-based power electronics.