Plasma-enhanced thermal nitridation of silicon

Abstract

A new procedure for plasma-enhanced thermal nitridation of silicon is reported. Highly purified ammonia plasma is generated in a quartz tube by radio-frequency power heating induction-coupled and SiC-coated carbon susceptors. This system requires no additional electrode in the reaction environment. At a substrate temperature of 1050 °C, thermal silicon nitride films with a thickness above 100 Å are grown for 150 min in background pressures ranging from 10−1 to 10 Torr. The films have a refractive index of 1.90, oxygen contamination of less than 10%, and an etching rate two orders of magnitude smaller than that of a thermal SiO2 film in a solution of NH4F:HF = 7:1.