Deposition of Cr films by hot target magnetron sputtering on biased substrates

The Cr films were deposited by hot target magnetron sputtering on grounded and biased substrates. The deposition modes with low and high deposition rates (different by 4 times) were selected. The sublimation of hot Cr target decreased the re-sputtering effect of the growing films under ion bombardment and reduced the losses of deposition rate from 28.7 to 13.4% (for −40 V bias and 1.9 kW discharge power). The calculations of energy flux density on the substrate revealed that the major contribution has a target radiation (56.2…85.5%) and kinetic energy of deposited particles and ions (4.8…34.3%) become a significant only with substrate biasing. The XRD measurements showed cubic structured (110) Cr films with compressive stresses (0.48…0.90 GPa), which is non-dependent from bias voltage for high-rate deposition modes. The Cr films mainly had a columnar structure and columnar width increased from 50 to 450 nm with rise of discharge power (W). The substrate biasing and high deposition rate resulted in the formation of irregular microstructure of the Cr films along their thickness from porous to columnar state. The indentation tests showed the strong dependence of film hardness and toughness (H/E) from W and different behavior of the mechanical properties of the Cr films for the deposition on biased substrates with low and high deposition rates.