Si nanoadhesion layer for enhanced SiO2-SiN wafer bonding

Highlights: → SiO2-SiN wafer was demonstrated using Si nanoadhesion layer at room temperature. → Upon the Si nanoadhesion layer, strong and tight bonding. → Transmission electron microscopy revealed that the SiO2-SiO2 interface tightly bonded. → We believe that this technique can promote the future 3D integration -- An SiO2-SiN wafer was produced using an Si nanoadhesion layer at room temperature. The two surfaces were cleaned by Ar ion beam activation and deposited with an Si nanoadhesion layer. Using such a layer, strong and tight bonding between SiO2 and SiN wafers was obtained without heat treatment. Transmission electron microscopy revealed that the SiO2-SiO2 interface was tightly bonded and is defect free. Moreover, the formation of an amorphous Fe-doped Si layer across the interface was found to enhance SiO2 wafer bonding. In addition, the Fe-Si amorphous layer was shown to have a resistance of 5 kΩ cm-1.