Influence of film thickness on the morphological and electrical properties of epitaxial TiC films deposited by reactive magnetron sputtering on MgO substrates

• TiC thin films were epitaxially grown up to a thickness of 545 nm on MgO (001) by DC reactive magnetron sputtering.
• Low electrical resistivity, ~160 µΩ cm, atomically flat epitaxial TiC films where grown up to a thickness of 57 nm.
• The surface morphology of films thicker than ~85 nm is dominated by nanoislands/nanocolumns.
• TiC/MgO films are subjected to compressive strain (1.5–0.6%); the TiC material relaxes with increasing of the film thickness.

Epitaxial TiC films were deposited on MgO (001) by DC magnetron sputtering in a reactive atmosphere of Ar and CH4 at 800 °C. The films elemental composition and chemical bonding was investigated by Auger electron spectroscopy (AES), X-ray photoelectron spectroscopy (XPS) and micro-Raman spectroscopy. The crystallographic structure, investigated by X-ray diffraction, exhibited an increased degree of (001) orientation with the film thickness, with a cube-on-cube epitaxial relationship with the substrate. The films morphology and electrical properties were determined by atomic force microscopy (AFM) and Hall measurements in Van der Pauw geometry. The influences of the film thickness (57–545 nm) on the morphological and electrical properties were investigated. The thinnest film presented the lowest resistivity, ~160 µΩ cm, showing an atomically flat surface, while higher values were obtained for the thicker films, explained by their different morphology dominated by low aspect ratio nanoislands/nanocolumns.