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 (100) substrate when the acceleration voltage was higher than 20V. The XPS depth profile indicated that nitrogen diffused to a depth of 36 nm for acceleration voltages of 60V and higher. The thickness of the silicon nitrided layer increased with the acceleration voltages from 20V to 60V. Cross-sectional transmission electron microscopy (TEM) analysis indicated a Si3N4 layer thickness of 3.1 nm was obtained at an acceleration voltage of 100V. 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. (C) 2015 Elsevier B.V. All rights reserved.