Peculiarities of time-dependent-dielectric breakdown characteristics of pure and doped Ta2O5 stacks

The effect of both the process-induced defects and the dopant on the time-dependent-dielectric breakdown in Ta2O5 stacks is discussed. The breakdown degradation is analyzed in terms of specific properties of high-k stacks which make their dielectric breakdown mechanism completely different from that of classical SiO2. The relative impact of a number of factors constituting the reliability issues in Ta2O5-based capacitors (trapping in pre-existing traps, stress-induced new traps generation, the presence of interface layer at Si and the role of the dopant) is clarified.