2026-10-14T04:03:48Z https://www.scidb.cn/oai

10.57760/sciencedb.43708 2026-07-21T16:10:48Z

2026-07-21 A New SiC/Diamond Engineered Substrate Enabling High-Temperature (300 °C), High-Power (PDC,max≥ 60 W/mm) GaN HEMTs for RF and Power Applications doi:10.57760/sciencedb.43708 en Despite widely pursuing diamond integration to mitigate GaN thermal bottlenecks, current methods remain constrained by thermal budget and thermal boundary resistance (TBR) challenges. Here we propose and demonstrate a novel 4H-SiC/diamond engineered substrate capable of directly supporting high-quality, front-end MOCVD GaN epitaxy. The platform is realized by transferring a ~1 μm single-crystal 4H-SiC trimming layer onto a polycrystalline diamond substrate. Through advanced bonding and trimming engineering, the 4H-SiC/diamond TBR is reduced to a record-low 8.45 m²·K·GW⁻¹ among all reported SiC/diamond interfaces. Leveraging this engineered substrate and pristine GaN-on-SiC epitaxy, the fabricated GaN HEMTs show exceptional high-temperature stability. We report the first demonstration of GaN HEMT dynamic stability at 300 °C, showing <3% current collapse under drain-lag pulse I-V measurements. Furthermore, both the power device figure-of-merit (BV2/RON,SP) and the ideal RF output power density (IDS·(BV-VKNEE)/8) benchmark among the highest in GaN devices reported for operation above 150 °C. Exploiting this high-temperature operation capability, the device achieves a maximum DC output power (PDC,max) of 60 W/mm at 100 oC ambient temperature, which is among the highest reported for GaN HEMTs to date. These results validate the proposed GaN-on-4H-SiC/diamond engineered substrate as a highly disruptive platform for future extreme-environment RF and power electronics GaN HEMTs; 4H-SiC/diamond engineered substrate; heterogeneous integration; thermal boundary resistance; high-temperature electronics deng ke xin Yipei RESTRICTED dataset Science Data Bank