Chemical Oxide Interfacial Layer for the High-$k$ -Last/Gate-Last Integration Scheme

The authors propose a high-
k
-last with gate-last integration scheme with a chemical oxide interfacial layer (IL). It was found that chemical oxide IL could form Hf-silicate at the high-
k
/IL interface so as to provide us a larger effective
k
value and a smaller equivalent oxide thickness (EOT). It was also found that the larger leakage current density for the samples with chemical oxide IL could be effectively suppressed by postdeposition annealing (PDA). Furthermore, it was found that PDA-induced larger EOT could be reduced by optimizing the metal gate stack.