Synthesis and study of highly dense and smooth TiN thin films

• Published in: arXiv.org 2020-06
• Main Authors: Chowdhury, Susmita, Gupta, Rachana, Prakash, Shashi, Behera, Layanta, Phase, D M, Gupta, Mukul
• Format: Article
• Language: English
• Subjects: Ambient temperature; Crystal defects; Density; Electrical resistivity; Electronic structure; High temperature; Ion beam sputtering; Partial pressure; Reaction kinetics; Reciprocity; Reduction; Reinforced reaction injection molding; Roughness; Substrates; Surface kinetics; Thin films; Titanium nitride
• ISSN: 2331-8422

This study aims towards a systematic reciprocity of the tunable synthesis parameters - partial pressure of N\(_2\) gas, ion energy (\Ei) and Ti interface in TiN thin film samples deposited using ion beam sputtering at ambient temperature (300\,K). At the optimum partial pressure of N\(_2\) gas, samples were prepared with or without Ti interface at \Ei~=~1.0 or 0.5\,keV. They were characterized using x-ray reflectivity (XRR) to deduce thickness, roughness and density. The roughness of TiN thin films was found to be below 1\,nm, when deposited at the lower \Ei~of 0.5\,keV and when interfaced with a layer of Ti. Under these conditions, the density of TiN sample reaches to 5.80(\(\pm\)0.03)\,g~cm\(^{-3}\), a value highest hitherto for any TiN sample. X-ray diffraction and electrical resistivity measurements were performed. It was found that the cumulative effect of the reduction in \Ei~from 1.0 to 0.5\,keV and the addition of Ti interface favors (111) oriented growth leading to dense and smooth TiN films and a substantial reduction in the electrical resistivity. The reduction in \Ei~has been attributed to the surface kinetics mechanism (simulated using SRIM) where the available energy of the sputtered species (\Esp) leaving the target at \Ei~= 0.5\,keV is the optimum value favoring the growth of defects free homogeneously distributed films. The electronic structure of samples was probed using N K-edge absorption spectroscopy and the information about the crystal field and spin-orbit splitting confirmed TiN phase formation. In essence, through this work, we demonstrate the role of \Esp~and Ti interface in achieving highly dense and smooth TiN thin films with low resistivity without the need of a high temperature or substrate biasing during the thin film deposition process.