Gettering in silicon-on-insulator wafers with polysilicon layer

We have studied both experimentally and theoretically iron gettering behavior in silicon-on-insulator (SOI) wafers. We show that a deposition of a polysilicon layer between the buried oxide and the device layer is a convenient way to have an effective gettering layer for metals in bonded SOI wafers under various processing conditions. Both our experiments and simulations show that the polysilicon layer decreases the dissolved iron concentration in the device layer and most importantly decreases the precipitation of the metals on the wafer front surface.