Effect of Power and Nitrogen Content on the Deposition of CrN Films by Using Pulsed DC Magnetron Sputtering Plasma

CrN thin films are deposited on stainless steel (AISI-304) substrate using pulsed DC magnetron sputtering in a mixture of nitrogen and argon plasma. Two set of samples are prepared. The first set of sample is treated at different powers (100 W to 200 W) in a mixture of argon (95%) and nitrogen (5%). The second set of samples is treated at different nitrogen concentrations (5% to 20%) in argon (95% to 80%) for a constant power (150 W). X-ray diffraction (XRD) analysis exhibits the development of new phases related to different compounds. The crystallinity of CrN varies by varying the applied power and nitrogen content. Crystallite size and residual stresses of the CrN (111) plane show similar variation for the applied power and nitrogen contents. Scanning electron microscopy (SEM) analysis shows the formation of a granular surface morphology that varies with the change of powers and nitrogen content. The thickness of the film is measured using SEM cross sectional images and using atomic force microscopy (AFM) scratch analysis. The maximum film thickness (about 755 nm) is obtained for the film deposited at 5% nitrogen in 95% argon at 150 W power. For these conditions, maximum hardness is also observed.