In this work, we investigate the effect of precursor flow conditions on the properties of the SiN film deposited by PECVD, and the related impacts on the device performance as well as hot-carrier reliability of NMOSFETs. We found that SiN film with higher nitrogen content possess larger tensile stress and thus higher on-current. Moreover, lower hydrogen contained in the SiN boosts the immunity to hot-carrier stress. Both demands can be fulfilled by increasing the N2 gas flow rate during SiN deposition. The lateral distribution of interface state generation after hot-carrier stress was also investigated.