Single-Crystal 4H/3C-SiC Engineered Substrate: A Novel Platform Enabling High-Performance Low-Voltage SiC Devices

4H-SiC devices are usually considered uncompetitive for low-voltage applications due to substrate resistance limitations. This work challenges this long-held belief by demonstrating a novel 150 mm single-crystal 4H/3C-SiC engineered substrate with resistivity over 45× lower than conventional 4H-SiC. The engineered substrate leverages the ultra-low resistivity of 3C-SiC and overcomes its high defect density by integrating a ~580 nm prime-grade 4H-SiC template. This template is transferred via surface-activated bonding and ion-cut onto a liquid-phase-grown 3C-SiC substrate. A sharp, defect-free bonding interface was achieved with a potential barrier below 30.4 mV and a record thermal boundary resistance of 1 + 0.7/–0.6 m2·K/GW. 200 V Schottky barrier diodes (SBDs) fabricated on this substrate demonstrate a record low specific on-resistance (Ron,sp) of 0.50 mΩ·cm2and a surge current tolerance over 300 A—representing a 47% reduction in Ron,spand a 20% increase in surge current robustness compared to identical devices fabricated on 4H-SiC substrates. The results establish a scalable hetero-integration material platform for enabling next-generation low-voltage SiC power electronics.