Iron segregation in silicon‐on‐insulator wafer with polysilicon interlayer

Abstract

We have studied iron gettering from monocrystalline silicon device layer into polycrystalline silicon (polysilicon) interlayer in thick bonded silicon‐on‐insulator (SOI) wafers. The results show that the polysilicon interlayer acts as an efficient gettering layer for iron. The gettering takes place via both the segregation and precipitation although the dominant gettering mechanism is segregation at low contamination levels. The activation energy of the segregation coefficient between the monocrystalline silicon and the polysilicon interlayer was found to be Ea = 1.9 ± 0.2 eV.