Abstract
The objective is to investigate the substrate bias effect on the structure and properties of the TiZrN thin films. The TiZrN thin films were deposited by DC unbalanced magnetron sputtering system (UBMS) with dual guns (Ti,Zr) targets onto Si (100) substrates at different substrate bias ranging from －35V to －150V. Experimental results indicated that all the specimens have strong (111) texture in XRD patterns. In this study, we discovered a transition bias of －35 V, above which a significant improvement of properties was found, including high hardness, excellent brilliance, low resistivity and fine surface morphology. Within the bias range of －40 to －120 V, the hardness of TiZrN films is around 35.5 GPa, the resistivity is about 33.5μΩ-cm, and the brilliance is larger than 80. The roughness is between 0.5 nm and 0.6 nm. The TiZrN films maintain excellent properties through a large range of applying bias, indicating that the process window is considerable wide. However, structure damage and thin film delamination were found when substrate bias reached －150V. The RBS result and SEM image further support the structure damage at －150 V. For protective coatings, low residual stress is required to avoid delamination. By adjusting substrate bias, residual stress can be controlled to lower value. In this study, the residual stress of TiZrN films gradually decreases with decreasing the substrate bias ranging from －65V to －35V. The TiZrN thin films with high hardness, lower residual stress could be obtained simultaneously at low substrate bias of －40V and －45V, the hardness and residual stress are 33.4～34.5GPa and －2.7 ～－3.7GPa, respectively.