Suppression of boron penetration into an ultra-thin gate oxide (/spl les/7 nm) by using a stacked-amorphous-silicon (SAS) film

The effect of boron penetration through an ultra-thin oxide (/spl les/7 nm) can be suppressed by using a stacked-amorphous-silicon (SAS) gate structure for pMOSFET. The SAS gate capacitor exhibits a smaller flat-band voltage shift, a lesser charge trapping and interface state generation rate, and a larger charge-to-breakdown than those of the as-deposited poly-Si (ADP) gate capacitor. The SiO/sub 2Si and poly-Si/SiO/sub 2/ interfaces of the SAS gate are also much smoother than those of the ADP gate,.<
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