The optimization of a slot waveguide for any specific application requires a study of the modal characteristics for a wide range of design parameters. Rigorous numerical methods, such as the finite element method (FEM), are time consuming and require a large amount of memory. In this paper, a simple semi-analytical method is used to analyze silicon slot waveguides and to optimize the performance of the waveguide for maximum power confinement in the slot, minimum effective mode area of the slot and to obtain flat dispersion characteristics. The results obtained by the present method agree well with the rigorous numerical results.