Contributions and limits of charge pumping measurement for addressing trap generation in high-k/SiO2 dielectric stacks

The relevance of charge pumping (CP) measurements for addressing reliability issues is investigated. This analysis points to the formation of defects in the interfacial SiO₂ layer induced by the high-k film and enhanced when increasing the high-k thickness or the temperature anneal. Then, combined with stress under substrate injection regime, CP reveals a generation of defects within the interfacial layer (IL) that could support TDDB results which suggest a breakdown initiated in the IL. Nevertheless, as far as high-k traps are involved, like in PBTI, CP turns out to be insufficient because of its probing depth limitation.