Structural and Electrical Properies of Photo-CVD Silicon Nitride Film

Abstract

Silicon nitride film was deposited by mercury-sensitized photochemical vapor deposition (photo-CVD) utilizing a gaseous mixture of SiH₄ and NH₃ under 253.7 nm ultraviolet light irradiation. The structural and electrical properties of the film were then evaluated with emphasis on the substrate temperature dependence. The film contains a considerable amount of hydrogen, and less dense than silicon nitride film deposited by high-temperature chemical vapor deposition. The structural properties of photo-CVD silicon nitride film are basically similar to those of silicon nitride film deposited by plasma-enhanced chemical vapor deposition (P-CVD). However, the film has better insulating properties than P-CVD film, with a smaller leakage current, a higher breakdown field and a smaller positive charge density within the film.