【Member Papers】1.5 kV β-Ga₂O₃ vertical Schottky diodes with 58 A surge current and off-state stressing study

      Researchers from the Xidian University have published a dissertation titled "1.5 kV β-Ga₂O₃ vertical Schottky diodes with 58 A surge current and off-state stressing study " in Applied Physics Letters.

Project Support

      We would like to thank the funding support in part from the National Natural Science Foundation of China (NSFC) with the Grant Nos. 62222407 and 62421005 and in part from Guangdong Basic and Applied Basic Research Foundation with Grant No. 2023B1515040024.

Background

      Beta-gallium oxide (β-Ga₂O₃) has rapidly emerged as a leading candidate for next-generation power electronics, primarily due to its ultra-wide bandgap of 4.8 eV, high critical electric (E)-field of ~8 MV/cm, and decent electron mobility of 200 cm²/V s, all of which contribute to its exceptional material properties. Coupled with the capability to produce large-area, cost-effective substrates through melt-grown methods, β-Ga₂O₃ is being advanced as a promising platform for high-performance power devices. Despite these strengths, achieving the theoretical performance limit of β-Ga₂O₃ remains challenging, particularly due to difficulties in managing the E-field at the device edge and the lack of effective p-type doping. Nonetheless, research efforts have led to innovative device architectures, with reported breakdown voltage (BV) exceeding 10 kV and power figures of merit (P-FOM) surpassing 10 GW/cm², underscoring β-Ga₂O₃’s potential for high-power and high-voltage applications in the evolving landscape of power electronics.

Abstract

      This study advances the development of vertical, large-area (3 × 3 mm²) β-Ga₂O₃ Schottky barrier diodes (SBDs) by incorporating double field plates and N ion implantation-based edge terminations (ETs) to significantly enhance the breakdown voltage (BV). By using ETs to suppress the concentrated electric field (E-field) at the anode edge, we achieved a BV of 1.5 kV with a specific on-resistance (R_on,sp) of 9.2 mΩ cm². The diodes demonstrated a forward current (I_F) of 11.2 A at 2 V and an impressive peak surge current of 58 A, with corresponding surge energy and power of 2.24 J and 553 W, respectively. Despite being 44% larger, our SBD exhibited a low reverse recovery time and negligible reverse loss, comparable to commercially available high-specification 30 A SiC diodes. Furthermore, even under stress at −1 kV for 10³ s, V_on shifted only slightly by 0.1 V, and ΔR_on,sp increased by just 4.9%. The diode also demonstrated exceptional robustness at elevated temperatures, with an I_F decrease in only 24% at 175 °C. These simultaneously achieved I_F, BV, and R_on, and surge characteristics highlight the potential of β-Ga₂O₃ SBDs as next-generation commercial high-voltage, industrial-level power electronics devices.

Conclusion

      In conclusion, we have developed an effective structure to enhance the BV of large-area vertical β-Ga₂O₃ SBDs by utilizing double FPs and ion-implanted ETs to manage the E-field at the anode edge. A high BV of 1.5 kV, I_F of 11.2 A at V_F = 2 V, and a surge current of 58 A were simultaneously achieved. Along with T-robust I_F and negligible reverse recovery losses, these performances significantly surpass those of other high-current and high-voltage β-Ga₂O₃ SBDs, demonstrating the immense potential of β-Ga₂O₃ SBDs for future high-power electronic applications.

FIG. 1. (a) 3D cross-sectional schematic view of the β-Ga₂O₃ SBD with DFPs-IP ETs. (b) C–V characteristic and extracted N_D = 6 × 10¹⁵ cm^-3 of the β-Ga₂O₃ SBD with an area of 9 mm². (c) Photograph of the devices and the devices after being packaged.

FIG. 2. (a) A photograph of a classic board-level double-pulse test. (b) Schematic circuit of the test corresponding to (a). (c) Reverse recovery comparison of β-Ga₂O₃ SBD and SiC JBS diode when recovered from 30 A. (d) Enlarged view of the dashed region in (c). (e) Surge current and voltage waveforms of the β-Ga₂O₃ SBD array under an 8.3 ms half-sine pulse. (f) The corresponding surge energy and power at various surge currents.

 

DOI：

doi.org/10.1063/5.0260146