A better understanding of CMOS latch-up

Both lumped-element two-transistor circuit model and two-dimensional finite-element analyses are used to study the latch-up phenomena in CMOS structures. The equivalent circuit model offers a simple view on latch-up, while 2-D modeling provides more physics and quantitative understanding of latch-up. A generalized criterion for p-n-p-n latch-up is derived based on the equivalent circuit. 2-D modeling confirms the latch-up triggering condition described by the criterion. Furthermore, 2-D simulation models the entire latch-up process, including the dynamic triggering stage, and determines the intrinsic steady-state I - V characteristics of p-n-p-n devices.