An integral injector-victim current transfer model for latchup design rule optimization

This work introduces a derivative-based model to describe the transfer between injector and victim during negative DC current stress. Geometric variation of the guardring width, victim size and injector size are included as linear corrections to a reference dependency for the transfer. Furthermore, the trigger current during external latchup is modeled for a range of victim sizes. A model involving a uniform current distribution in the victim n-well can explain the results. The injector-victim current transfer model and trigger current model are combined to extract maximum allowed well-tap distances. Options to improve the accuracy of latchup design rules are discussed.