Differentiation between Electric Breakdowns and Dielectric Breakdown in Thin Silicon Oxides

It has been known for some time that non-destructive electric breakdowns precede destructive thermal dielectric breakdown. We have been studying both processes in oxides between 5 nm and 80 nm in thickness. We have shown that the electric breakdowns can trigger dielectric breakdown under certain conditions. This triggering of dielectric breakdown causes TDDB distributions to be nonunique. The TDDB distributions could be shifted to shorter times if a) the impedance of the test equipment was lowered and/or b) the capacitance of the test equipment was raised. The implications of this work will be discussed in terms of electric/dielectric breakdown models and practical circuit and device operation.