Flat-band voltage shifts in p-MOS devices caused by carrier activation in p/sup +/-polycrystalline silicon and boron penetration

Abstract
We found that the annealing time dependence of the flat-band voltage (V/sub FB/) shift of a p/sup +/-polysilicon gate MOS diode is attributed to the activation of boron in the polysilicon instead of the boron penetration through the gate SiO/sub 2/. We identified the process window for p/sup +/-polysilicon gate pMOSFETs taking into account that boron is sufficiently activated in polysilicon without penetrating through the gate SiO/sub 2/.