Effect of the substrate bias voltage on the mechanical properties of nanocomposite CrZrSiN thin films

Nanocomposite CrZrSiN thin films were deposited with various substrate bias voltages from 0 to -200 V using unbalanced magnetron sputtering. The crystalline structure, microhardness, microstructure, and adhesion properties of the CrZrSiN thin films were evaluated by X-ray diffraction, Fischer scope, field-emission scanning electron microscopy, and a scratch tester. The surface roughness and deposition rate decreased with an increase in the substrate bias voltage. The substrate bias voltage increased and the hardness increased to 36 GPa at -100 V, then decreased to 32 GPa as the substrate bias voltage further increased to -200V. The CrZrSiN thin films maintained their hardness up to 800 degrees C while the hardness of CrZrN film decreased rapidly over 500 degrees C. The critical load (Lc3) increased from 8 N to 35 N up to a substrate bias voltage of -100 V, while the critical load decreased to 8 N with further increase of the substrate bias voltage.