A zone-based approach for physics-based FET compact models

Abstract

Equivalent circuit field-effect transistor models (compact models) are extensively used in integrated circuit design and manufacture. The most commonly used models are not derived from basic physical fundamentals, but are rather determined by parameter extraction techniques from experiment. This requires that the device be fabricated and characterized before the model can be determined. An alternate approach is to derive the model from fundamental physics, which permits the model to be used in device design as well as circuit applications. In this work a zone-based approach to physics-based compact model development is described. The approach starts from fundamental physical principles and produces a model that accurately describes the dc and RF performance of the device. The zone-based approach divides the device into zones based upon operational physical phenomena. The various zones are described with a simplified set of equations, and the zones are then linked to form the complete model. The physics-based approach produces a compact model that can easily be formulated to include all pertinent physical phenomena known to affect device performance. The zone-based approach yields a flexible device model that is both quantitatively accurate and easy to employ in system level simulators.