Anomalous reverse short-channel effect in p/sup +/ polysilicon gated P-channel MOSFET

The boron-penetration-dependent Reverse Short Channel Effect (RSCE) on the threshold voltage is observed for short channel p/sup +/ poly-gate PMOSFET's. The RSCE is found to be more significant as the boron penetration becomes more severe. The RSCE is significant in BF/sub 2/ doped poly-gated MOS devices and is alleviated in buffered poly-gated MOS devices. Fluorine enhanced boron diffusion in the gate oxide during high temperature process is believed to account for the RSCE, which is also confirmed by using a two-dimensional process simulator.<
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