p/sup +/ polysilicon gate P-MOSFETs using BCl implantation

Suppressing boron penetration through the gate oxide is necessary to give reliable p/sup +/ polysilicon gate P-MOSFETs which are expected to ease the short channel effect. Fluorine was automatically introduced in the gate oxide by BF/sub 2/ implantation and enhanced B diffusion. It is clearly demonstrated that chlorine does not enhance B diffusion. BCl implantation when fabricating p/sup +/ polysilicon gates makes it possible to fabricate quarter-micron gate length P-MOSFETs with pure oxide 4.5 nm thick.<
>