Characteristics of nanostructure and electrical properties of Ti thin films as a function of substrate temperature and film thickness

Titanium films of different thickness at different substrate temperatures are prepared using PVD method. The nanostructure of these films was obtained using X-ray diffraction (XRD) and AFM, while the thicknesses were measured by means of Rutherford back scattering (RBS) technique. Resistivity, Hall coefficient, concentration of carriers and the mobility in these films are obtained. The results show that, the rutile phase of TiO2 is formed which is initially amorphous and as the film thickness increases it tends to become textured in (020) direction, which is more pronounced at higher temperatures and possibly transforms to anatase TiO2 with (112) orientation for thickest films of 224 nm. The conductivity and concentration of carriers increase with thickness, while the Hall coefficient and the mobility decrease. The activation energies in these samples were obtained from the Arrhenius plots of σ and RH. For thinner films ( \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document} $$ E_{\hbox{a}} \approx 0.4 - 0.6 $$\end{document} eV) and for thickest film (224 nm) a break point is observed at about 500 K, which is consistent with the idea of more processes becoming activated at higher temperatures.