Stress-controlled silicon nitride film with high optical transmittance prepared by an ultrahigh-vacuum electron cyclotron resonance plasma chemical-vapor deposition system

Abstract

An ultrahigh-vaccuum electron cyclotron resonance plasma chemical-vapor deposition system with a substrate heating component has been applied to deposit silicon nitride film. Low background pressure (∼5×10−9 Torr) and efficient plasma excitation at a low deposition pressure (<10−3 Torr) result in a low oxygen impurity content in the silicon nitride film. Process flexibility of this system, i.e., control of the SiH4 to NH3 flow ratio, deposition pressure, and substrate temperature, allows the deposition of near-stoichiometry silicon nitride film with a high optical transmittance as well as a suppressed amount of hydrogen impurity and a low film stress.