Oxide thickness dependence of nitridation effects on TDDB characteristics

Using wet oxide thickness ranging from /spl sim/50 to 80 /spl Aring/, effects of nitridation on time-dependent dielectric breakdown (TDDB) characteristics have been investigated. Results show that capacitors with nitrided oxide have shorter t/sub bd/ up to a thickness of /spl sim/60 /spl Aring/ but turnaround behaviour was found for /spl sim/50 /spl Aring/ nitrided oxide. It is suggested that the turnaround behaviour of t/sub bd/ of nitrided wet oxide of /spl sim/50 /spl Aring/ 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 /spl Aring/ for the same nitridation conditions.