Structural, optical and electrical properties of argon implanted TiN thin films

Abstract

Modification in structural, optical and electrical properties of titanium nitride (TiN) thin films induced by argon ion irradiation and thermal annealings was studied using various experimental techniques. TiN thin films deposited by dc reactive sputtering on Si substrate were implanted with argon ions at 200 key. As-implanted samples were annealed before or after ion irradiation at 600 degrees C and 700 degrees C, respectively. Rutherford bacicscattering spectrometry, X-ray diffraction, cross-sectional (high-resolution) transmission electron microscopy, spectroscopic ellipsometry and electrical measurements were carried out in order to study structural, optical and electrical properties of TiN/Si samples. After irradiation with 200 keV Ar ions the columnar microstructure of TiN was changed and the presence of smaller crystalline grains was observed. Partial Los's of columnar structure observed in implanted samples was completely recovered after annealing at 700 degrees C. Observed changes in microstructure induced by ion irradiation and annealings were correlated with the variation in optical parameters obtained by spectroscopic ellipsometry. It was found that both refractive index and extinction coefficient are strongly dependent on the defects' concentration and size of the crystalline grains in TiN layers. (C) 2014 Elsevier Ltd. All rights reserved.