The present invention includes an advanced MOSFET design and manufacturing approach
that allow further increase in IC packing density by appropriately addressing the
increased leakage problems associated with it. The MOSFET according to one embodiment
of the present invention includes a gate, source/drain diffusion regions on opposite
sides of the gate, and source/drain extensions adjacent the source/drain diffusion
regions. The MOSFET also includes at least one added corner diffusion region that
overlaps with at least a portion of a source/drain extension region for reducing
off-state leakage currents. The corner diffusions can be created using conventional
CMOS IC fabrication processes with some modification of an ion implant mask used
in manufacturing a conventional CMOS IC.