Interfacial Engineering of SiC/Si Heterostructures via Surface-Activated Direct Bonding: Crystallographic Orientation Effects and Stress Mitigation Strategies
Xiao Qin, Jieqiong Zhang, Lichao Wu, Xu Chen, Beitian Zheng, Matthias Danner, Michael Dornetshumer, Florian Medl, Tobias Wernicke, Anli Yang, Ge Jiang, Mingsheng Fang, Wei Xiong, Guodong Xiong, Zhe Xu, Jun Liu, Houzhao Wan, Hao Wang, Wenhan Bao, Changlin Wu, Hei WongAbstract
This work presents a comparative study of heterojunctions based on 6-inch wafers between silicon carbide and silicon (including Si-face of 4H-SiC and Si, and C-face of 4H-SiC and Si) fabricated via low temperature surface-activated bonding performed on the EVG ComBond system. We systematically investigate crystallographic orientation-dependent effects on interfacial structure and rigorously characterize internal stress distributions within wafer-bonded heterojunction structures through advanced analytical techniques. The interfacial layer properties and mechanical bonding strength are quantitatively assessed. For the first time, in situ heating transmission electron microscopy reveals real-time low-temperature recrystallization at the heterogeneous bonding interface. Our results establish fundamental correlations between process parameters and interfacial integrity, providing insights into the physical mechanism of SiC/Si heterostructures using advanced low-temperature wafer bonding technology. These findings provide guidance for the robust development of SiC/Si heterojunctions and highlight their potential for next-generation wafer-level packaging in high-power and extreme-environment electronics.