Silicon nitride (SIN(x)) films were prepared by ion-assisted deposition process. The films were analyzed by measurement of scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FTIR), X-ray photoelectron spectrometry, spectrophotometer, and ellipsometer measurements. The effects of N-ion current density (J) on the structural and optical properties of SiN(x) thin films were investigated. The SEM studies revealed that films deposited at a higher value of J had highly condensed structure. FTIR analysis indicated an extremely low hydrogen content in the IAD films. It was found that the N/Si ratio of films increased when J increased. The optical constants and the optical band gap of films were determined. The stoichiometric Si(3)N(4) thin film was obtained with a high refractive index of 2.073 (at a wavelength of 400 nm), an extinction coefficient less than 6 x 10(-4), and an optical band gap of 4.57 eV. (C) 2010 Elsevier B.V. All rights reserved.