Total Pressure Effects on the Properties of Silicon Nitride Films Fabricated by Photoenhanced Chemical Vapor Deposition

Abstract

Silicon nitride ( SiNx ) films were deposited on (100)Si substrates using silane and ammonia gases by the direct-photolysis photoenhanced chemical vapor deposition method at 280° C. The depositions were performed with emphasis on the total pressures, which ranged from 0.51 Torr to 4.04 Torr. As the total pressure increased, the film resistivity decreased from 3.7×1015 Ω· cm to 4.8×109 Ω· cm. The effective trapped carrier density at the SiNx /(100)Si interface reached a minimum value (2.1×1010 cm-2) at 1.52 Torr. The film included silicon bonded with silicon (Si–Si) components as well as nitrified silicon (Si–N) components. The Si–Si components increased and the Si–N components decreased in number as the total pressure increased. Based on these results and gas analysis findings, two important reactions to characterize the film properties were discussed.