Detection of junction spiking and its induced latch-up by emission microscopy

Electrical-overstress/electrostatic-discharge-induced latch-up failures have been observed on both MOS field and simulated failures. Using emission microscopy, this failure mode is determined to be due to junction spikings which form a p⁺ doped junction, creating a parasitic p.n.p.n. structure and inducing a localized SCR latch-up. A model for this failure mode is presented. The emission microscope readily locates the exact contact at which junction spiking occurs even in complex VLSI devices. Its characteristic emission pattern allows the failure mechanism to be determined without further destructive physical analysis. It provides a visual proof that current crowding occurs around the contacts during high-current events