For short-channel submicron MOS devices, we present a unified current equation, which covers both weak and strong inversion. The current in weak inversion is controlled by the subthreshold slope, for which we derive a new physics-based, predictive model. Furthermore, a new model for the carrier mobility is presented, which allows to derive closed-form current equations with good scalability. The approaches have been implemented in the compact model PREDICTMOS and are qualified by comparison with numerical device simulations and measurements. (C) 2004 Elsevier Ltd. All rights reserved.