Effects of constant voltage stress in Hf-doped Ta2O5 stacks

Conduction mechanisms in Hf-doped Ta
₂
O
₅
stacks (7; 10 nm) under the constant voltage stress (CVS) are probed by the SILC analysis. The low field conduction is ascribed to trap-assisted tunneling, and the Poole-Frenkel effect dominates at medium and high fields. Stress affects the pre-existing traps and their energy levels, but does not create additional traps. The thinner layers exhibit better temperature and electrical stability after CVS.