New boundary conditions and a 2D potential distribution along the channel of a high-k gate-dielectric MOSFET,including both the gate dielectric material region and the depletion region,are given.Based on this distribution,a 2D threshold-voltage model with the fringing-field and short-channel effects is developed for a high-k gate-dielectric MOSFET.The model agrees well with experimental data and a quasi 2D model,and is even more accurate than the quasi 2D model at higher drain voltages.Factors affecting the threshold behavior of the high-k gate-dielectric MOSFET are discussed in detail.