Electrical conductivity enhancement of epitaxially grown TiN thin films

Titanium nitride (TiN) presents superior electrical conductivity with mechanical and chemical stability and compatibility with the semiconductor fabrication process. Here, we fabricated epitaxial and polycrystalline TiN (111) thin films on MgO (111), sapphire (001), and mica substrates at 640 degrees C and room temperature by using a DC sputtering, respectively. The epitaxial films show less amount of surface oxidation than the polycrystalline ones grown at room temperature. The epitaxial films show drastically reduced resistivity (similar to 30 micro-ohm-cm), much smaller than the polycrystalline films. Temperature-dependent resistivity measurements show a nearly monotonic temperature slope down to low temperature. These results demonstrate that high-temperature growth of TiN thin films leads to significant enhancement of electrical conductivity, promising for durable and scalable electrode applications.