High-temperature N ion implantation for performance-enhanced current-blocking layers in β-Ga2O3

This work reveals the significant advantages of high-temperature nitrogen (N) ion implantation for fabricating current-blocking layers (CBLs) in β-Ga2O3. A comparative investigation on the structural and electrical properties of N-implanted β-Ga2O3 was conducted under different implantation temperatures and post-implantation annealing (PIA) conditions. The results showed that the high-temperature implantation (HTI) at 500 °C, compared to the room-temperature implantation (RTI), introduced fewer structural defects and less lattice distortion to β-Ga2O3. The HTI-formed CBL demonstrated a far superior current-blocking capability than those formed by the RTI with/without a PIA, in terms of a much lower and more stable leakage current and a significantly enhanced breakdown voltage. Additionally, lateral MOSFETs fabricated with the HTI isolation exhibited a three orders of magnitude lower off-state leakage current while maintaining excellent on-state performance, compared to those using the isolation formed by RTI with PIA. These findings indicate that the in situ dynamic annealing effect of HTI effectively reduces implantation-induced damage, enhances impurity activation, and improves the overall performance of the N-implanted CBLs in β-Ga2O3.