Enhancement-Mode $\beta$ -Ga2O3 Current Aperture Vertical MOSFETs With N-Ion-Implanted Blocker

Enhancement-mode (E-mode) vertical β-Ga
₂
O
₃
metal-oxide-semiconductor (MOS) field-effect transistors featuring a current aperture were developed on a single-crystal β-Ga
₂
O
₃
(001) substrate. Nitrogen ions were implanted into a drift layer grown by halide vapor phase epitaxy to form current blocking layers (CBLs) for vertical source-drain isolation, while Si ions were implanted to form degenerately doped source contact regions and a top-gated lateral channel that was fully depleted at 0-V gate bias. The devices delivered a high output current on/off ratio of 2×10
⁷
despite a nonideal MOS interface that limited the maximum drain current density to <; 0.1 kA/cm
²
. Pulsed operation without current collapse under off-state voltage stress was demonstrated. Hard breakdown occurred prematurely owing to leakage through the CBLs, but is expected to improve with an optimized nitrogen implantation process. The realization of E-mode vertical Ga
₂
O
₃
transistors based on a manufacturable all-ion-implanted process represents an important step toward practical applications of Ga
₂
O
₃
power electronics.