Structure and mechanical properties of titanium nitride thin films grown by reactive pulsed laser deposition

Abstract

Titanium nitride (TiN) thin films as a hard coating were grown on a Si (100) as a substrate by reactive pulsed laser deposition (reactive PLD). To investigate the effect of substrate temperature and the pressure of nitrogen (N2) gas on the structural and mechanical properties of the as-grown TiN thin films, we varied the substrate temperature and working pressure during the deposition process. X-ray diffraction (XRD) measurements showed that the as-grown TiN thin films at 10−3 torr (13 × 10−2 Pa) and 450℃ grew preferentially in the direction of the (111) plane. Nano-indentation measurements showed that the hardness and elastic modulus value of the as-grown TiN thin films at 10−3 torr (13 × 10−2 Pa) and 450 ℃ were higher than with other deposition conditions. In addition, the (111) texture coefficients obviously increased for the as-grown TiN thin films at 10−3 torr (13 × 10−2 Pa) and 450℃, as compared with as-grown TiN thin films with other deposition conditions; generally, an increase of the (111) texture coefficient resulted in an increase of the hardness. A field emission scanning electron microscope (FESEM) study of microstructural measurements showed that a dense columnar structure was observed with a high (111) texture coefficient while a granular structure was observed at the other deposition condition. A correlation of the reactive pulsed laser deposition parameters with the structural and mechanical properties of as-grown TiN thin films is discussed in this paper.