Structure and Morphology Study of Very Thin TiCrN Films Deposited by Unbalanced Magnetron Co-sputtering

摘要

Very thin titanium chromium nitride (TiCrN) films with various Ti content were deposited by unbalanced magnetron co-sputtering of Ti and Cr metals. Deposition time was set to 15 min to achieve film thickness ranging from 142 to 190 nm. Silicon wafers and copper grids were used as substrates. The Ti current (I_(ti)) was varied from 0.4 to 1.0 A to achieve the differnt Ti content whereas Cr current (I_(Cr)) was fixed to 0.6 A. Effects of the Ti content on structure and morphology of these TiCrN thin films were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), atomic force microscopy (AFM), field emission scanning electron microscopy (FE-SEM), and energy-dispersive X-ray spectroscopy (EDS). The XRD revealed that the films showed crystalline structure with fcc phase and were formed as Ti_xCr_(1-x)N solid solution with a crystallite size of about 13 nm. The TEM result confirmed that the films were polycrystalline. The AFM images of the films showed dome top characteristic with root-mean-square roughness slightly decreasing from 1.643 to 1.273 nm. FE-SEM cross-sectional images exhibited development of film morphology from columnar structure corresponding to zone 1 of Thornton's structure zone model to fine structure gradually with the increase of the Ti content.