Comprehensive investigation of GaN and AlN-on-GaN JBS diodes: optimizing inter-p + spacing for high-power applications

Abstract A thorough investigation of Gallium Nitride and Aluminum Nitride-on-Gallium Nitride Junction Barrier Schottky diodes, focusing on inter-p + spacings of 0.5 to 2.5 μm, was conducted to optimize the performance for high-power, high-frequency, and high-temperature applications. This study addresses a gap in the existing research by systematically examining the impact of inter-p + spacing over a wide range, providing critical insights for practical designs and applications. The optimal Junction Barrier Schottky spacing was identified as 1–1.3 μm for fully Gallium Nitride-based diodes and 1.1–1.4 μm for Aluminum Nitride/Gallium Nitride diodes, revealing significant improvements over standard designs. For an intrinsic layer thickness of 0.5 µm, the best trade-off between specific on-resistance and breakdown voltage is achieved at 1.2 μm spacing for Gallium Nitride-based diodes, yielding a specific on-resistance of 9.93 × 10−3 mΩ cm2, a breakdown voltage of 185.72 V, a critical electric field of 3.75 MV/cm, and a Baliga’s Figure of Merit of 3.47 GW/cm2. While Aluminum Nitride/Gallium Nitride diodes at 1.4 μm spacing achieve optimal performance with a specific on-resistance of 3.63 × 10−3 mΩ cm2, a breakdown voltage of 156.98 V, a critical electric field of 4.32 MV/cm, and a Baliga’s Figure of Merit of 6.78 GW/cm2. This research demonstrates the superior performance of Junction Barrier Schottky diodes compared to PiN diodes under forward bias and Schottky diodes under reverse bias conditions. Notably, the Aluminum Nitride/Gallium Nitride diodes exhibit an unprecedented Baliga’s Figure of Merit, setting a new benchmark in the field. These findings pave the way for the next generation of high-efficiency, high-reliability power devices by demonstrating the transformative potential of optimized inter-p + spacings in Junction Barrier Schottky diode design.