Effect of nitrogen plasma on the mechanical and electrical properties of plasma-enhanced atomic layer deposited TiN films

Superior electrical and mechanical properties, such as low electrical resistivity and good adhesion with substrate, are required to apply titanium nitride(TiN) films processed by plasma-enhanced atomic layer deposition(PEALD) to components such as thin film electrodes or bipolar plates for fuel cells. Herein, we elucidate the effect of plasma parameters in PEALD process on electrical and mechanical properties of TiN films. The effect of nitrogen plasma exposure time and power during the PEALD process are evaluated, and composition, morphology, mechanical and electrical properties of TiN films according to the nitrogen plasma parameters are systematically studied. Consequently, we show that highly dense (up to 93% of the bulk density) and crystallized (grain size up to 40 nm) TiN films are deposited with minimal inclusion of impurities at higher nitrogen plasma power and longer plasma exposure time during the PEALD process. In particular, the adhesion of the PEALD TiN films with Si substrates enhances by 50% with strong dependence on plasma power rather than plasma exposure time. The results of this study may have implications for applying TiN thin films with improved mechanical stability and electrical conductivity to various applications by controlling the plasma parameters during the PEALD process.