AVS 49th International Symposium
    Thin Films Tuesday Sessions
       Session TF-TuM

Paper TF-TuM1
Mechanical Properties of TiN and Ti@sub 1-x@Si@sub x@N@sub y@ Coatings using Surface Acoustic Wave Techniques

Tuesday, November 5, 2002, 8:20 am, Room C-101

Session: Mechanical Properties of Thin Films
Presenter: D.C. Hurley, National Institute of Standards and Technology
Authors: D.C. Hurley, National Institute of Standards and Technology
A.J. Richards, CSIRO, Australia
V.K. Tewary, National Institute of Standards and Technology
A. Bendavid, CSIRO, Australia
P.J. Martin, CSIRO, Australia
Correspondent: Click to Email
Surface acoustic wave (SAW) spectroscopy is a nondestructive, noncontacting technique to determine thin-film mechanical behavior. In some cases, it may be more suitable than other, more conventional methods. The approach involves optical generation and detection of SAWs over a bandwidth of several hundred megahertz. Measurements of the SAW displacement versus propagation distance allow the frequency dependence of the phase velocity (dispersion relation) to be determined. Quantitative values for properties like Young's modulus E and film thickness d are obtained by comparing the dispersion data to analytical models. Our model allows analysis for anisotropic film properties and uses an elastodynamic Green's function method. We illustrate our techniques with results on TiN and Ti@sub 1-x@Si@sub x@N@sub y@ coatings for enhanced wear resistance. In TiN films prepared with filtered-arc physical vapor deposition techniques, E increased from 368 to 453 GPa with increasing d and decreasing compressive residual stress. SAW results were in good agreement with those from two destructive methods: instrumented indentation techniques (IIT) for E and scanning electron microscopy for d. Ti@sub 1-x@Si@sub x@N@sub y@ films with a nanocomposite structure were prepared by concurrent reactive deposition of Ti by a cathodic arc source and Si by a magnetron sputter source. Values greater than 40 GPa for the microhardness H were measured by IIT. SAW and IIT values for E were in good agreement and ranged from 325 to 417 GPa. Both H and E were observed to depend on the magnetron power or atomic per cent of Si in the films. From these results the ratio H/E, an indicator of wear resistance, was found to be relatively high.