An Analytic Surface-Field-Based Quasi-Atomistic Model for Nanowire MOSFETs With Random Dopant Fluctuations

For the first time, an analytic surface-field-based model for nanowire MOSFETs with random dopant fluctuations (RDF) is reported. In this model, the depletion charge due to the discrete dopant distribution is described by the Dirac δ functions, while the mobile charge keeps its continuous form. By introducing two new variables, the discrete 1-D Poisson´s equation is transformed into a simple algebraic equation to correlate the surface potential with the field (due to the inversion charge). Without solving the potential distribution, the drain current can be calculated from the Pao-Sah integral using the oxide-interface boundary condition. This model is shown to be more accurate in predicting the RDF effects than the continuous TCAD simulations for all the operating regions. We also discuss the RDF-incorporated short-channel effects by solving the discrete 2-D Poisson´s equation in the subthreshold regime.