Study of Random-Dopant-Fluctuation (RDF) Effects for the Trigate Bulk MOSFET

A study of random-dopant-fluctuation (RDF) effects on the trigate bulk MOSFET versus the planar bulk MOSFET is performed via atomistic 3D device simulation for devices with a 20 nm gate length. For identical nominal body and source/drain doping profiles and layout width, the trigate bulk MOSFET shows less threshold voltage (V
_th
) lowering and variation. RDF effects are found to be caused primarily by body RDF. The trigate bulk MOSFET offers a new method of V
_TH
adjustment, via tuning of the retrograde body doping depth, to mitigate tradeoffs in V
_TH
variation and short-channel effect control.