β-Ga₂O₃ junction barrier Schottky diode with NiO p-well floating field rings

Abstract

Recently, β-Ga2O3, an ultra-wide bandgap semiconductor, has shown great potential to be used for power devices blessed to its unique material properties. For instance, the measured average critical field of the vertical Schottky barrier diode (SBD) based on β-Ga2O3 has reached 5.45 MV/cm, and no device in any material had measured a greater before. However, the high electric field of the β-Ga2O3 SBD makes it challenging to manage the electric field distribution and leakage current. Here, we show that β-Ga2O3 junction barrier Schottky diode with NiO p-well floating field rings (FFRs). For the central anode, we filled a circular trench array with NiO to reduce the surface field under the Schottky contact between them to reduce the leakage current of the device. For the anode edge, experimental results have demonstrated that the produced NiO/β-Ga2O3 heterojunction FFRs enable the spreading of the depletion region, thereby mitigating the crowding effect of electric fields at the anode edge. Additionally, simulation results indicate that the p-NiO field plate structure designed at the edges of the rings and central anode can further reduce the electric field. This work verified the feasibility of the heterojunction FFRs in β-Ga2O3 devices based on the experimental findings and provided ideas for managing the electric field of β-Ga2O3 SBD.