Effects of sputtering current on the bonding structure and mechanical properties of diamond‐like carbon films deposited by MFPUMST

Diamond‐like carbon (DLC) films on glass wafers were produced by middle frequency pulsed unbalanced magnetron sputtering technique (MFPUMST) at different sputtering current. The chemical bonding of carbon characterized by Raman spectroscopy and X‐ray photoelectron spectroscopy (XPS) show that the sp³ fraction in DLC films increases with increasing sputtering current from 100 to 300 mA, and then decreases above 300 mA. Mechanical properties like nano‐hardness and elastic recovery for these films under different sputtering currents analyzed by a nano‐indentation technique show the same tendency that nano‐hardness and elastic recovery increase with increasing sputtering current from 100 to 300 mA, and then decrease with increasing sputtering current from 300 to 400 mA. These results indicate that the sp³ fraction in the prepared DLC films is directly related to nano‐hardness and elastic recovery. The results shown above indicate that the parameter of the preparation—sputtering current has a strong influence on the bonding configuration of the deposited DLC films. The mechanism of sputtering current on the sp³ fraction is discussed in this paper. Copyright © 2009 John Wiley & Sons, Ltd.