Investigations on RF sputtered TiN thin films and Cu/TiO 2 /TiN devices for resistive switching memory applications

The growth of titanium nitride (TiN) thin films with bulk TiN conductivity for inert electrode applications remains a challenge, owing to various microstructural and compositional properties. Here, we report the fabrication of TiN thin films using optimised RF magnetron sputtering, where deposition conditions were tailored to achieve metal like electrical conductivity in TiN films. The TiN thin films deposited at 750 °C and in pure nitrogen ambient, revealed the minimum resistivity of ~ 26 µΩ cm, matching bulk TiN and suitable for electrode applications. The TiN thin films were used as bottom electrode to fabricate Cu/TiO 2 /TiN devices, which demonstrated repeatable non-volatile bipolar resistive switching characteristics with good endurance, retention, and multibit capability. The resistive switching and current conduction mechanisms of the device were explained considering Cu atom constituting filamentary switching, caused due to electrochemical metallization. The switching parameters and mechanism of TiO 2 based devices using TiN bottom electrode were found to be similar to those observed in Pt based RRAM devices, demonstrating TiN films’ capability as an effective substitute for noble metal electrodes. This study may aid in the development of device grade metal like conducting TiN thin films, which are potential alternate to noble metal electrodes for resistive switching memory applications.