Analysis of the breakdown spots spatial distribution in large area MOS structures

The spatial distribution of multiple breakdown (BD) spots in large area MOS structures was investigated. By means of applying image processing and point pattern analysis techniques we provide for the first time direct evidence that the BD spots´ locations are spatially uncorrelated as expected for a Poisson process. For completeness, we show how the available mathematical tools might be utilized to detect interactions (repulsion or attraction) between the spots as well as weak regions in the dielectric layer. In this way, the methods considered here can complement standard reliability techniques based on a large set of samples.