Quantum mechanical enhancement of the random dopant induced threshold voltage fluctuations and lowering in sub 0.1 micron MOSFETs

A detailed study of the influence of quantum effects in the inversion layer on the random dopant induced threshold voltage fluctuations and lowering in sub 0.1 micron MOSFETs has been performed. This has been achieved using a full 3D implementation of the density gradient (DG) formalism incorporated in our previously published 3D ´atomistic´ simulation approach. This results in a consistent, fully 3D, quantum mechanical picture which implies not only the vertical inversion layer quantisation but also the lateral confinement effects manifested by current filamentation in the ´valleys´ of the random potential fluctuations. We have shown that the net result of including quantum mechanical effect, while considering statistical fluctuations, is an increase in both threshold voltage fluctuations and lowering.