TDDB evaluation of plasma-enhanced Si3N4 nitride capacitors in CMOS integration schemes

We present constant voltage (CV) time-dependent dielectric breakdown (TDDB) measurements of integrated metal-insulator-metal (MIM) capacitors with plasma-enhanced chemical vapor deposited Si₃N₄ nitride (PEN) dielectric. We demonstrate tight breakdown distributions for the capacitors in a full-flow Al-based integration scheme. We achieved these excellent results by design rules to reduce plasma damage, careful process control, and an appropriate treatment of process variability. These results are superior to previously published reports that showed much wider fail time distributions for similar dielectrics and integration schemes. We also demonstrate promising performance for PEN MIM capacitors in a short-flow Cu-based integration scheme. Finally, we discuss application of several possible models ("E," "√E," and "I/E") to the data for predicting the PEN lifetime at operating conditions.