High-Performance GaN HEMTs on an Ultrathin 4H-SiC/Diamond Engineered Substrate via Optimized Epitaxial Growth

GaN high-electron-mobility transistors (HEMTs) were fabricated on an ultrathin 4H-SiC/diamond engineered substrate using an optimized epitaxial growth scheme. Optimization of the epitaxial growth conditions improved epitaxial quality and carrier transport properties.The fabricated devices exhibited a maximum DC drain current density of approximately 1.25 A/mm and a peak transconductance of 367 mS/mm, demonstrating high current capability on the engineered substrate platform. Infrared thermography yielded a low-power thermal resistance of 0.92 K•mm/W, compared with 2.46 K•mm/W for a GaN-on-SiC reference device.The device on the engineered substrate sustained a maximum DC power dissipation density of 37.8 W/mm. These results demonstrate the potential of the optimized GaN-on-4H-SiC/diamond platform for high-performance GaN devices with enhanced thermal management.