A unified approach, particularly suitable for evaluation of high-k stack structures, is presented. This approach is based on fully self-consistent solutions to the Schrodinger and Poisson equations. Various structures and materials of high-k stacks of interest have been examined and compared to access the reduction of gate current in these structures. The present approach is capable of modeling high-k stack structures consisting of multiple layers of different dielectrics. The results of gate current and capacitance obtained from our model are in very good agreement with experimental data. (c) 2006 Elsevier Ltd. All rights reserved.