Analysis of the variation in the electrical performance of integratedcircuit structures requires a knowledge of the distributions and inter relationships of device parameter values. This article presents new techniques for more accurate transistor modeling and describes the statistical characterization procedure developed to describe the inte grated circuit manufacturing process as far as the measurable elec trical parameters are concerned.1108 THE BELL SYSTEM TECHNICAL JOUBNAL, APBIL 1971 *The choice of parameter names for the transport model are identical with the CIRCUS' convention; the injection model parameter names are selected to prevent ambiguity. The parameters used are defined in Table I.