Effect of silicon nitride deposition parameters on TDDB performance of SiNx-MIM capacitors

Abstract

Silicon nitride (SiNx) is commonly used as the dielectric or insulator material for metal-insulator-metal (MIM) capacitors. The deposition of SiNx can be performed using plasma-enhanced chemical vapor deposition (PECVD) method with different deposition parameters by changing individually the SiH4 flow rates, NH3 flow rates, RF power, substrate temperature, etc. Time-dependent dielectric breakdown (TDDB) is the most important reliability test item to check the intrinsic performance of the MIM capacitor dielectrics. In this study, the effect of several SiNx deposition parameters on the dielectric TDDB performance of SiNx MIM capacitors has been studied: silane (SiH4) gas flow rate, RF power and ammonia (NH3) gas flow rate. The constant voltage TDDB lifetime performances for different conditions were compared and discussed for MIM capacitor optimization and the mechanism behind the effect was discussed.