Appl. Phys. Lett., 86, 111902 (2005). [pdf]


Unusual Stress Behavior in W-incorporated Hydrogenated Amorphous Carbon Films


Yi-Ying Wang, Hyo-Shin Ahn, Kwang-Ryeol Lee and Jae-Pyoung Ahn


Unusual stress behavior was observed in W-incorporated hydrogenated amorphous carbon films prepared by a hybrid process composted of ion beam deposition and magnetron sputtering. As the tungsten concentration increased from 0 to 2.8 at.%, the residual compressive stress decreased by 50%, without significant deterioration in the mechanical properties. This was followed by a rapid increase and a gradual decrease in the residual stress with increasing W concentration. High-resolution TEM analysis and first-principle calculations show that the reduced directionality of the W-C bonds in the W incorporated amorphous carbon matrix relaxes the stress caused by the distorted bonds.