Characterization of TiN thin films grown by low-frequency (60 Hz) plasma enhanced chemical vapor deposition

The characteristics of TiN thin films grown on glass substrates by very low frequency (60 Hz) PECVD were investigated along with the reactive plasma generated using a 60 Hz power source. The TiN film depositions were performed using a gaseous mixture of H2, N2 and TiCl4 onto a substrate positioned between two electrodes using a floating substrate holder with a heating unit. The substrate is electrically floated to avoid sample damages due to ion bombardment. As-grown TiN films showed a NaCl-type fcc structure with a (200) crystallographic plane, low resistivity (∼60 μΩ cm) and gold-like color. Crystallinity was improved, impurities such as O and Cl were reduced, and the atomic ratio of N/Ti became stoichiometric with the increase of substrate temperature. Particularly, no chlorine component was detected above 500 °C. Also, the N2 partial pressure strongly affected the deposition rate and ratio of N/Ti. Otherwise, impurities and crystallinity barely changed with the change of N2 pressure. The atomic ratio of N/Ti, impurities, and crystallinity of the films significantly affected the optical and electrical properties. Consequently, we produced stoichiometric Cl-free TiN films with golden color above 500 °C at 60 mTorr. The effects of temperature played an important role in controlling the film properties compared to the N2 partial pressure.

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► TiN films were grown on glass substrates using a low-frequency (60 Hz) PECVD.
► TiN film depositions were carried out in the glow discharge region.
► Chlorine-free TiN films with (200) growth plane were acquired above 400 °C.
► Ratio of Ti to N was controlled according to temperatures and N2 pressures.
► Properties of TiN films were strongly dependent on temperature and N2 pressure.