Room temperature bonding of diamond/Si with Mo/Au interlayers in atmospheric air

The room temperature bonding of diamond and silicon wafers with Mo/Au nano-adhesive interlayers was realized in atmospheric air. The scanning acoustic microscopy and scanning electron microscopy analyzation results exhibit extremely low voidage and uniform intermediate layer at the heterointerface. The bonding strength was sufficiently high (7.78 MPa) so that fracture within silicon occurred in the tensile test. Additionally, the X-ray photoemission spectroscopy results also indicate that the fracture mainly occurred in bulk silicon, rather than Au/Au, Mo/Au, Mo/diamond and Mo/Si interfaces, demonstrating a stronger bonding strength than that of bulk Si. The TEM observations suggested that such strong bonding was attributed to atomic diffusion and grain growth across the Au/Au bonding interface and chemical reactions at Mo/Si and Mo/diamond interfaces. These results may provide an alternative approach for the combination of diamond and silicon.