Characterization of low-k SiOCH dielectric for 45 nm technology and link between the dominant leakage path and the breakdown localization

Electrical characterizations have been performed on porous low-k SiOCH dielectric used in the 45 nm technology. The present paper demonstrates that the conduction follows the Poole–Frenkel (PF) mechanism at medium and high fields. The apparent deviation from the PF mechanism at high field is explained by the trapping phenomenon due to the large amount of defects in the dielectric. This trapping deforms the band diagram and lowers the electron injection within the dielectric. A study of two key process steps is also performed and shows that the dominant conduction mechanism localization (bulk versus interface) is not necessarily at the origin of the breakdown mechanism.