Characterization of the bonding strength and interface current of p-Si/n-InP wafers bonded by surface activated bonding method at room temperature

Bonding between p-Si and n-InP was performed through the surface activated bonding method at room temperature. Tensile results show that the samples were visibly separated from the bonded interface, indicating a weak bonding strength. The cause of the weak bonding strength was intensively investigated. Consistent results between x-ray photoelectron spectroscopy and atomic force microscope investigations show that a weak phase of indium is terminated on the InP due to the depletion of phosphorus in the sputtered surface. Existence of indium layers on the debonded Si surface indicate that the samples were separated from the interface of In/InP, but not across the bonded interface of Si and indium. Typical pn junction current–voltage behavior indicates no high resistance interface layer that can withstand the flow of current through the interface. Remarkably, sputtering time as well as energy dependence on the interface current is found to be due to the accumulation of sputtering induced defects.