Structural, electro-optical, and mechanical properties of reactively sputtered (TiZrHf)N coatings

Abstract

Within the frame of this work, reactive magnetron-sputtered (TiZrHf)N coatings were deposited on Si substrates. The depositions were carried out from a pure TiZrHf target with varying N2-to-total (N2+Ar) flow ratios, RN. The TiZrHf alloy and its nitride coatings exhibited body-centered cubic and face-centered cubic crystal structures, respectively. The increase in RN contributed to the decrease in O2 contamination. For nitrides, with increasing RN, the grain size decreased to a nano-sized level. Consequently, the microstructure of the nitride coatings was converted from a large columnar structure with rough surface to a fine columnar structure with a smooth surface. Moreover, the compressive stress and the corresponding lattice parameter increased initially and then decreased. The golden-like (TiZrHf)N coatings deposited at RN=20% exhibited the highest hardness of 40.7 GPa, which attained the superhard grade. Meanwhile, low electrical resistivity of 129.2 μΩ-cm and high reflectivity at 0.62 eV of 84.0% were obtained. The electro-optical behavior of (TiZrHf)N coatings was demonstrated further by spectroscopic ellipsometry on the basis of their dielectric function and energy loss function. The gold-colored (TiZrHf)N coating with excellent physical properties has a wide range of diverse potential industrial applications.