EBIC/PL investigations of dislocation network produced by silicon wafer direct bonding

Dislocation networks (DNs) formed by silicon wafer bonding were studied by means of Electron Beam Induced Current (EBIC) and Photoluminescence (PL). The measurements were performed on p-n junction diode structures prepared by ion implantation. EBIC signal was observed not only inside the diode structure, but also far outside the diode area. This finding demonstrates the ability of the bonding interface to efficiently collect minority carriers and indicates a high electrical conductivity of the dislocation network. In addition, circular inhomogeneities of charge collection were observed. The contrast of those regions was bright at high beam energies and turned dark or vanished at lower energies. The contrast behavior of the circular areas can be explained by local variations of collection efficiency and recombination at the DN, which might be a result of different density of oxide precipitates. PL mappings at 0.794 and 1.081 eV revealed similar circular areas.