New gettering using misfit dislocations in homoepitaxial wafers with heavily boron‐doped silicon substrates

The gettering mechanism due to misfit dislocations in P/P+ epitaxial wafers is clarified for copper‐diffused epitaxial wafers. The epilayer thickness of the sample is 2.2 μm and the substrate resistivity of the sample is 0.0015–0.002 Ω cm. It is dipped in a Cu(NO3 )2 ‐HF solution and annealed at 900 °C for 30 min. The in‐depth Cu profile obtained by secondary‐ion mass spectroscopy shows a distinctive peak at the P+ ‐substrate side in the vicinity of the epi/sub interface. This peak coincides with that of dislocation density for their location in depth. Furthermore, from energy dispersive spectroscopy observation the diffused copper is found to be effectively gettered at misfit dislocations as copper silicide from moire fringe.