Nitrogen-Implanted Guard Rings for 600-V Quasi-Vertical GaN-on-Si Schottky Barrier Diodes With a BFOM of 0.26 GW/cm²

This work demonstrates a novel Nitrogen-implanted (N-implanted) guard ring (GR) technology for the 600-V quasi-vertical GaN-on-Si Schottky barrier diode (SBD). The GR parameters are designed and studied in detail by the TCAD simulation. With a 4.4-μm-thick GaN drift layer, seven GRs with a precise design greatly enhance the breakdown voltage of GaN SBDs from ~290 to ~600 V, and barely degrade the on-state characteristics, including a high $I_{{on}}/I_{{off}}$ of 10¹¹, a low ideality factor of 1.06, a low turn-on voltage of 0.64 V (at 1 A/cm²), and a low-specific on-resistance ( $R_{{on},sp}$ ) of 1.40 mΩ · cm², leading to a record Baliga's figure of merit (BFOM) of 0.26 GW/cm² among all the reported vertical GaN-on-Si SBDs. At 175 °C, the SBD with seven GRs shows a slightly increased $R_{{on},sp}$ of 1.86 mΩ · cm² and an excellent electrical characteristic even under a reverse bias of 380 V, implying a high-temperature operation capability of N-implanted GRs.