Polarization Effect Induced by Discrete Impurity at Semiconductor/Oxide Interface in Si-FinFET

The random dopant fluctuation (RDF) is a dominant source of statistical variability for nano-scale metal-oxide-semiconductor-field-effect-transistors (MOSFETs). We study RDF with the polarization effect induced by the discreteness of impurity and the dielectric mismatch at the Si/oxide interface by 3D drift-diffusion simulation. The charge distribution model employed in this study for the discrete impurity clarifies RDF dependence on the dielectric constant of oxide material. It is shown that explicit modeling of the polarization charge associated with discrete impurities is inevitable for reliable prediction of threshold voltage.