Analysis of capacitor breakdown mechanisms due to crystal-originated pits

The extent to which crystal originated defect pits (COPs) will enhance capacitor B-mode failures has been examined as a function of substrate carrier type/dopant concentration and bias mode (accumulation/inversion). An unexpected immunity to COPs, found for n-type capacitors biased into accumulation, could be readily explained by invoking Fowler-Nordheim (FN) tunneling variations due to the morphology of the capacitor electrodes, as revealed by cross-sectional TEM on simulated COPs formed by KOH anisotropic etching.