A new surface-potential-based MOSFET model that independently accounts for the quantum mechanical effects (QME) in the accumulation and inversion regions is proposed. The quantum modeling of the accumulation layer relies on the triangular potential well approximation whereas the variational approach to the solution of the Schrodinger and Poisson equations is used for the inversion layer. Using no additional parameter, our quantum relationships offer simple expressions in terms of process parameters and bias. The resulting model is fully dependent on all terminal voltages and gives an accurate description of the surface potential and its derivatives in all regions of operation, from accumulation to inversion. The results of this compact model are compared with both self-consistent solutions of Schrodinger and Poisson equations, and experimental data. An excellent agreement is found for both I-V and C-V characteristics. (C) 2004 Elsevier Ltd. All rights reserved.