Fabrication of SiC/Si, SiC/SiO₂, and SiC/glass heterostructures via VUV/O₃ activated direct bonding at low temperature

Low-temperature direct bonding is an effective method for joining two dissimilar materials into one composite. In this paper, we developed a universal method for fabricating single-crystalline SiC on Si, SiO₂, and glass substrates via vacuum ultraviolet/ozone (VUV/O₃) activated direct bonding at 200 °C. Our studies showed that VUV irradiation could lead to hydrophilic and smooth surfaces to be bonded. TEM observations confirmed that the transition layers of SiC/Si, SiC/SiO₂, and SiC/glass direct bonded pairs were only nanoscale, which was beneficial for the miniaturization of power devices. On the basis of X-ray photoelectron spectroscopy (XPS) elemental depth profiles analysis, we also demonstrated that the enriched carbon layers at the bonding interfaces were originated from the SiC substrates during the VUV treatment. Additionally, the bonding mechanism was discussed combining all the experimental investigations.