A model for low-temperature operation of minority-carrier well-type guard rings in epitaxial CMOS structures

Abstract

As temperature is lowered, behaviors of well-type guard rings in an epitaxial substrate are quite different from those at RT so that the previous formulation is unable to reflect these discrepancies precisely. This leads to a new escape-current model suitable for low-temperature applications. In addition to the structural parameters, the new model is also functions of other physical quantities such as temperature, high-level injection, surface recombination velocity at the high/low junction and minority-carrier transport parameters, which are also important at low temperature. (C) 1997 Elsevier Science Ltd.