Silicon nitride (SiNx) began to be applied in the semiconductor industry in the late 1960s. As low-pressure chemical vapor deposition (LPCVD) technology developed, SiNx became widely used as a passivation layer and dielectric material due to its excellent barrier and mechanical properties. In the late 1980s, combined with its wide band gap of around 5 eV, SiNx started to be used in compound semiconductors (GaN, GaAs) for interface engineering.In this work, LPCVD SiNx was deposited under different temperatures (730℃, 750℃, and 770℃) and NH3/dichlorosilane (SiH2Cl2) gas ratios (9.8, 4.08 and 0.1), and metal-insulator-semiconductor (MIS) capacitors were subsequently fabricated. The refractive index, stress, and stoichiometry of SiNx were examined. The dielectric constant and breakdown field of LPCVD SiN were determined by C-V and I-V measurements. To further understand the dielectric breakdown mechanism and reliability under long-term electrical stress, time-dependent dielectric breakdown (TDDB) behaviors of LPCVD SiN in MIS capacitors were evaluated.