Physics-based Analytical Modeling of CMOS Latchup

Analysis of the steady-state Kirchhoff equations within the framework of a new physics-based equivalent circuit provides explicit expressions for the holding voltage and current for the resistive mode in bi-stable CMOS structures. The resulting expressions are functions of the physical parameters (temperature, doping level of the substrate, material band gap), which makes it possible to evaluate the influence of technological factors on the latchup parameters. In particular, an explicit formula was obtained for the critical charge for single event latchup as a function of process parameters and temperature.