Abstract
The objective of this study was to deposit thick TiN film without using Ti interlayer by adjusting process parameters of unbalanced magnetron sputtering (UBMS) system. The controlling deposition parameter was either the opening of gate valve between turbomolecular pump (TP) and deposition chamber or the pumping speed of TP. The flux of argon and nitrogen was adjusted at a fixed ratio to maintain the same working pressure in the chamber. The results showed that TiN film with a thickness of 7 μm could be successfully deposited and the residual stress was less than -2 GPa.. From XRD pattern, most of samples were with random texture. The N/Ti ratios of all samples were ranged from 1.0 to 1.1. Nanoindentation data ranging from 23~27 GPa indicated that hardness of the films was not related to the film thickness. All samples exhibited low electrical resistivity ranging from 14 to 25 µΩ-cm. The compressive residual stress of the TiN coatings mostly decreased with thickness for all three series of specimens. The stress gradient of the sample with a thickness of 7 m showed that the residual stress was fluctuated along the thickness. This stress fluctuating behavior may enable the growth of TiN coating up to 7 μm without spallation. By selecting proper operational parameters, the energy consumption of TP during deposition could be reduced and the maintenance duration of TP could be prolonged as well. The processing window for depositing thick TiN coatings in this research was quite wide, which is beneficial to the industrial applications.