Effect of Pulse Width and Frequency of Bias DC Voltage on the Microstructure of Pure Cr Coatings by Magnetron Sputter Ion Plating

Pure Cr coatings were deposited onto the pieces of silicon wafer at different pulse width and frequency of bias voltage by magnetron sputter ion plating.The microstructure and preferential orientation of pure Cr coatings were analyzed by SEM and XRD respectively.Results show that the diffusion ability of atoms on the coating surface was improved due to the substrate temperature rise effect caused by the ion bombardment with the pulse width increased.However,the effect of frequency of bias DC voltage on the microstructure of pure Cr coatings was particularly significant.The bombardment ions action on the coating surface were more uniformly and more dispersed compared with the nucleation rate of Cr atoms and the density of pure Cr coatings both improved with the frequency increased are the main reasons that the microstructure of pure Cr coatings changed from dense,granular columnar grain outcrops to uniformity,small nano-crystalline particles.