Thickness dependent microstructural and electrical properties of TiN thin films prepared by DC reactive magnetron sputtering

Abstract

Titanium nitride (TiN) thin films were prepared by direct current (DC) reactive magnetron sputtering with a pure Ti target in a N2 and Ar mixed atmosphere at 350°C on Si (100) substrates. The aim of the present work was to clarify the influence of thickness on film properties systematically. Results indicated that all the films were stoichiometric. The evolution of film roughness during growth process could be divided into two stages. In the early stage, surface roughness decreased with increasing thickness related to the presence of particles diffusion and smoothing the underlying Si substrates. In the later growth process, film surface was roughening with increasing thickness due to the shadowing effect and change of surface morphologies with different orientations. Moreover, film grain sizes and density monotonically increased with increasing film thickness, and preferred orientation also varied as a function of thickness. It was found that all the films had low resistivity (<7.5×10−7Ωm) and the lowest value of 5.4×10−7Ωm was obtained at about 140nm thick. Then the effect of film thickness on resistivity was discussed based on grain boundary and surface scattering.