Accurate TDDB Lifetime Prediction of High-k Stacked Gate Dielectrics with Regarding High Density Initial Traps

Abstract

Essentials required for the accurate TDDB lifetime (TBD) prediction of high-k stacked gate dielectrics are discussed. For this purpose, thorough understanding of the time dependent dielectric breakdown (TDDB) mechanism is indispensable, along with clarifying its stress gate voltage (VG) dependence. As for the TDDB mechanism, we propose the Generated Subordinate Carrier Injection (GSCI) model, which presumes that the degradation is dominated by the injected subordinate carriers (IDC). Because of the coexistence of the current component which does not contribute to the breakdown such as the trap-assisted current, the decomposition of the subordinate carrier current to each component is needed. On the other hand, to obtain the stress VGdependence of TBD, we point out the universal relationship between the voltage acceleration factor of TBD and the stress VG. It is demonstrated that the accurate lifetime prediction can be realized on the basis of the GSCI model combined with this universality.