Oxide thickness dependence of nitridation effects on TDDB characteristics

Using wet oxide thickness ranging from ~50 to 80 Å, effects of nitridation on time-dependent dielectric breakdown (TDDB) characteristics have been investigated. Results show that capacitors with nitrided oxide have shorter t_bd up to a thickness of ~60 Å but turnaround behaviour was found for ~50 Å nitrided oxide. It is suggested that the turnaround behaviour of t_bd of nitrided wet oxide of ~50 Å compared to the wet oxide seems to be due to the greater nitrogen concentration at the interface than for thick wet oxide of over 60 Å for the same nitridation conditions