Direct observation of the generation of breakdown spots in MIM structures under constant voltage stress

Abstract

Oxide reliability analysis in metal–insulator–metal and metal–insulator–semiconductor structures relies on electrical characterization methods like time-dependent dielectric breakdown (TDDB) tests. It has been demonstrated in previous studies that during a constant voltage TDDB test it is possible to detect the generation of multiple breakdown events in a single device. As we show in this paper, in some occasions, not only the time-to-breakdown but also the spatial location of each failure event over the device area can be recorded. This latest feature adds a new dimension to standard oxide reliability analysis since spatio-temporal statistics can be applied. A simple method for determining the generation rate and location of the breakdown spots in Pt/HfO2(30nm)/Pt structures based on image subtraction and thresholding is reported.