Composition, structure, and nanomechanical properties of DC-sputtered CrNx (0≤x≤1) thin films

Abstract CrN x (0≤ x ≤1) thin films were deposited on silicon (100) by DC reactive magnetron sputtering using a wide range of N 2 partial pressures. Composition and crystal structure were determined by X-ray photoelectron spectroscopy and X-ray diffraction, respectively. Nanoindentation hardness and reduced modulus were measured using a Hysitron nanomechanical properties system. Annealing effects on structure and mechanical properties were studied. The presence of Cr, Cr 2 N and CrN (and mixtures of these phases) has been confirmed and related to the average film composition. With a small amount of N 2 added ( p N 2 ∼0.5%) the strong Cr (110) peak disappears and the hardness of Cr increases significantly. Pure Cr 2 N was obtained for p N 2 in the range of 7.5–9.5%, while pure CrN was obtained for p N 2 >20% of the total pressure. The highest hardness was obtained for p N 2 in the range of 10–15% of the total pressure. During annealing (400°C, 2 h), a Cr 2 N (111) texture appeared for p N 2 in the range of 0.5–10.0% of the total pressure. The hardness and modulus of Cr, Cr 2 N and CrN increased after annealing.