Nitridation of silicon by nitrogen neutral beam

Graphical abstract: - Highlights: • Nitrided silicon was formed by nitrogen neutral beam at room temperature. • Si₃N₄ layer was formed at the acceleration voltage more than 20 V. • Formed Si₃N₄ layer show the effective as the passivation film in the wet etching process. - Abstract: Silicon nitridation was investigated at room temperature using a nitrogen neutral beam (NB) extracted at acceleration voltages of less than 100 V. X-ray photoelectron spectroscopy (XPS) analysis confirmed the formation of a Si₃N₄ layer on a Si (1 0 0) substrate when the acceleration voltage was higher than 20 V. The XPS depth profile indicated that nitrogen diffused to a depth of 36 nm for acceleration voltages of 60 V and higher. The thickness of the silicon nitrided layer increased with the acceleration voltages from 20 V to 60 V. Cross-sectional transmission electron microscopy (TEM) analysis indicated a Si₃N₄ layer thickness of 3.1 nm was obtained at an acceleration voltage of 100 V. Moreover, it was proved that the nitrided silicon layer formed by the nitrogen NB at room temperature was effective as the passivation film in the wet etching process.