Latent damage investigation on lateral non-uniform charge generation and stress-induced leakage current in silicon dioxides subjected to low-level electrostatic discharge impulse stressing

This paper reports on the generation of positive lateral nonuniform (LNU) charges in silicon dioxide (SiO₂), following low-level electrostatic discharge (ESD) stress using a transmission line pulsing technique. Using an array of charged equivalent small-area MOS capacitors with similar areas to represent the LNU charges, we can explain the effect of LNU charges on the experimental high frequency C-V (HFCV) curves. The formation of LNU charges was attributed to the localised injection of avalanche hot-carriers from the silicon substrate together with the accompanying impact ionisation within the oxide. A short stressing pulse duration was found to be critical for the LNU-charge formation, as uniform charge trapping will result for longer duration stress pulses. A relationship between the generated LNU charges and stress-induced leakage current (SILC) was also observed and discussed in this article