APL Materials, cilt.13, sa.8, 2025 (SCI-Expanded, Scopus)
A novel ion beam physical vapor deposition technique has been developed for TiN thin film deposition. The method uses only standard surface science tools, namely a cold cathode ion gun (normally used for sputter cleaning with Ar) operated with N2 gas and a modified titanium sublimation pump as a Ti PVD source. TiN thin films were deposited onto semi-insulating GaAs (001) substrates, and their physical and electrical properties were measured. X-ray photoelectron spectroscopy suggested predominantly TiN bonding with some oxynitride components. The DC conductivity increased in the range of 200-350 S/cm at temperatures ranging from 300 to 430 K. The behavior was consistent with the correlated barrier hopping model with an activation energy of 0.043 eV. The AC measurements (40 Hz to 0.2 MHz) indicated lower impedance above 10 kHz, possibly from the reduced effect of polarization at grain boundaries and other extended defects. The DC temperature dependence was also maintained even at the highest frequencies.