Computationally Efficient Substrate Noise Coupling Estimation in Lightly Doped Silicon Substrates

A Z-parameter based macromodel for characterizing the substrate noise coupling in a lightly doped substrate at low frequencies has been developed. The model is scalable with contact geometries and separation. The cross-coupling impedance between two contacts is modeled using an improved geometric mean distance formulation. This approach obviates the need for using several spacing related parameters for describing the contact separations, sizes, and orientation. An improved self-impedance model has also been developed. Proximity effects of neighboring contacts are taken into account by a paneling approach. The macromodel with paneling has been successfully used to predict the noise coupling for multi-contact examples. The errors from the macromodel relative to a numerical simulator are within acceptable limits of 15.