【Member Papers】High-performance and high-reliability Ga₂O₃ Schottky barrier diodes enabled by double-side packaging integrated with microchannel cooling

      Researchers from the Xidian University have published a dissertation titled "High-performance and high-reliability Ga₂O₃ Schottky barrier diodes enabled by double-side packaging integrated with microchannel cooling in International Journal of Thermal Sciences.

Project Support

      This work is supported by the National Natural Science Foundation of China (Grant No. 62304170 and 62374122), Guangdong Basic and Applied Basic Research Foundation (No. 2023B1515040024), Fundamental Research Funds for the Central Universities (No. ZYTS25302) and Xidian University Specially Funded Project for Interdisciplinary Exploration (No. TZJH2024057).

Background

      UWBG semiconductor Ga₂O₃ exhibits exceptional promise for power electronics due to its large bandgap (E_g) of 4.8 eV, ultrahigh critical breakdown electric field (>8 MV/cm), excellent saturation velocity (ν_s) of 2 × 10⁷ cm s⁻¹ and high BFOM of 3000. These intrinsic properties enable Ga₂O₃ SBD with significantly lower R_on compared to conventional semiconductors under equivalent voltage rating, thereby achieving reduced power loss and higher power conversion efficiency. Furthermore, the fabrication of large-diameter Ga₂O₃ wafer through scalable melt growth, which shares process similarity with sapphire wafer manufacturing, offers significant cost advantage over SiC and GaN technologies due to enhanced material yield and reduced production complexity. Therefore, Ga₂O₃ SBD integrates high breakdown strength, low conduction loss, and competitive manufacturing cost to enable breakthrough performance in ultrahigh-voltage, high-power-density, and energy-efficient systems.

Abstract

      Ultra-wide bandgap (UWBG) semiconductor Ga₂O₃ Schottky barrier diodes (SBDs) have emerged as a leading candidate for next-generation power electronics owing to its low on resistance, ultrahigh critical breakdown electric field and superior Baliga's figure of merit (BFOM). However, it suffers from severe self-heating due to ultralow thermal conductivity, which limits power density and reliability. Hence, an active thermal management strategy is proposed by integrating double-side packaging with microchannel cooling. Experimental results demonstrate a 66.6 % reduction in junction-to-ambient thermal resistance (R_j-a) from 39.8 K/W to 13.3 K/W and a maximum junction temperature drop of 58 %, achieving a low temperature of 88.6 °C at 4.5 W power dissipation. Electrically, the device exhibits a higher operating current of 1025.4 mA with 19.8 % enhancement at 3 V and a lower specific on-resistance (R_on) of 3.50 mΩ cm² with at least 12.1 % decrease, in comparison with the conventional bottom-side packaged SBD under natural convection cooling. Under prolonged on-state electrical stress testing at 2 V bias, the current exhibited merely 7.3 % degradation over 6000 s. The synergy of the proposed double-side packaging and optimized microchannel cooling shortens thermal pathway and suppresses hotspot formation, providing a critical solution for high-power-density electronics.

Conclusion

      This study demonstrates a double-side packaged Ga₂O₃ SBD integrated with microchannel cooling, overcoming thermal limitation imposed by the intrinsic ultralow thermal conductivity. The strategy achieves a record-low R_j-a of 13.3 K/W representing 66.6 % reduction and 58 % lower junction temperature at 4.5 W power dissipation. Electrically, near-junction heat extraction boosts current density to 512 A/cm² at 3 V with 19.8 % improvement and reduces R_on to 3.50 mΩ cm². Reliability tests show only 7.3 % current degradation after 6000 s stress, outperforming conventional packaging by 2.2 %. Microchannel integration further enhances cooling efficiency, yielding faster transient thermal response and sustaining junction temperatures at 72.8 °C at high power. The flip-chip interconnects synergize with microchannel flow to minimize thermal pathways for Ga₂O₃ SBDs, eliminating hotspot formation. Consequently, this co-design approach enables Ga₂O₃ SBDs to operate at unprecedented power densities while maintaining thermal-electrical stability, establishing a foundation for next-generation ultra-high-power electronics.