Over 1.3-kV β-Ga₂O₃ Vertical UMOSFET With High Concentration of N-Ion Implantation and Activation Annealing Temperature

In this article, we investigated the electrical characteristics of the high-voltage $\beta $ -gallium oxide (Ga2O3) vertical U-shaped trench gate MOSFETs (UMOSFETs) based on a current blocking layer (CBL) under varying nitrogen ions implantation concentrations and activation annealing temperatures. When the nitrogen ions implantation concentration is $4\times 10^{{19}}$ cm−3 and the activation annealing temperature is 1200 °C, the fabricated device achieved the highest breakdown voltage ( ${V} _{\text {br}}$ ) exceeding 1.3 kV without field plates, while obtaining an on-resistance ( ${R} _{\text {on}}$ ) of 132.35 m $\Omega \cdot $ cm2. Additionally, at a nitrogen ions implantation concentration of $2\times 10^{{19}}$ cm−3 and an activation annealing temperature of 1100 °C, the device achieved a ${V} _{\text {br}}$ of 985 V, R $_{\text {on}}$ of 24.37 m $\Omega \cdot $ cm2, and a power figure-of-merit (PFOM) of 40 MW/cm2. Our findings indicate that the current blocking capability of the CBL and Vbr improved with the increase in nitrogen ions implantation concentration and activation annealing temperature, while an increase in device R $_{\text {ON}}$ was observed. Overall, this work demonstrates the potential for achieving high-performance $\beta $ -Ga2O3 UMOSFETs with nitrogen ions implantation.