Remote nitridation of silicon surface by Ar/N2-fed expanding thermal plasma

Low temperature nitridation of native oxidized silicon surface using Ar/N2-fed expanding thermal plasma was investigated. Samples were exposed to the plasma downstream the arc nozzle. X-Ray photoelectron spectroscopy analysis showed that the nitrogen is chemically bonded to silicon, resulting in the change of the native oxide layer into an oxynitride layer. Secondary ion mass spectrometry and low energy ion scattering analyses provided the in-depth distribution of elements, showing that the oxynitride layer approximately reaches a thickness of 5 nm for a treatment time of 30 min. The plasma nitridation process has a passivation effect and provides the surface with increased etching resistance against Ar/SF6-fed expanding thermal plasma.