Kinetic Mechanism for Fabricating HWCVD Silicon Nitride Films Regulated by Hot-Wire Current and Substrate Temperature

<title>Abstract</title> <p>Silicon nitride thin films have important application value in the fields of semiconductor devices and optoelectronic devices because of the excellent mechanical strength, chemical stability and optical properties. Hot wire chemical vapor deposition technology has become an effective means to prepare high-quality silicon nitride thin films because of its advantages of high deposition rate and high gas utilization rate. In this study, hot wire current and substrate temperature were studied to prepare silicon nitride thin films through variable experiments and systematic regulation. The experimental results show that the increase of hot wire current can accelerate the decomposition of precursors and improve the deposition rate, and high current will reduce the uniformity of thin films due to excess kinetic energy of vapor particles. The films prepared at 32A current achieve the best match between optical properties and surface quality. The control of substrate temperature needs to balance the atomic mobility and thermal stress effect. The refractive index and passivation performance of the film are the best at 200 ℃, and the surface flatness is the best at 300 ℃. The lattice distortion caused by thermal stress accumulation after the temperature exceeds 300 ℃ will significantly reduce the density and optical properties of the film.</p>