Effect of Duty Cycle on Characteristics of CrN_x Thin Films Deposited by Pulsed Direct Current Reactive Magnetron Sputtering

摘要

CrN_x thin films have been deposited on silicon wafer, 304 stainless steel, and tungsten carbide substrates using pulsed DC reactive magnetron sputtering. A 10 kHz unipolar mode and a N_2/Ar ratio of 17.5% were used. During the deposition, the substrate was not biased and not heated during the entire deposition time of 30min. The microstructure, crystalline phase, and mechanical properties of the obtained CrN_x thin films were examined to investigate the effect of the duty cycle. The results show that the maximum current and power density increase with decreasing duty cycle from 100% (DC) to 5%. Although the thickness of the CrN_x thin films decreases with decreasing duty cycle, the ratio of the thickness to the pulse on-time shows a maximum of 273.3 nm/min at the lowest duty cycle of 5%. The obtained CrN_x thin films show a mixture of the Cr_2N and CrN phases. Moreover, the Cr-N bonding state and the percentages of CrN and Cr_2N vary with the duty cycle. The effects of the duty cycle on the hardness, coefficient of friction, and corrosion behavior of the CrN_x thin films are also investigated in this study.