A threshold voltage model for high-k gate-dielectric MOSFETs considering fringing-field effect

In this paper, a threshold voltage model for high-kappa gate-dielectric metal-oxide-semiconductor field-effect transistors (MOSFETs) is developed, with more accurate boundary conditions of the gate dielectric derived through a conformal mapping transformation method to consider the fringing-field effects including the influences of high-kappa gate-dielectric and sidewall spacer. Comparing with similar models, the proposed model can be applied to general situations where the gate dielectric and sidewall spacer can have different dielectric constants. The influences of sidewall spacer and high-kappa gate dielectric on fringing field distribution of the gate dielectric and thus threshold voltage behaviours of a MOSFET are discussed in detail.