Interaction between sputtered beta-Ta films and diamond-like carbon with Ru intermediate layer

Interaction between beta-tantalum film and Diamond-like Carbon (DLC) film was studied with and without ruthenium intermediate barrier layer. Phase identification using X-ray Diffraction showed that the phase transformation of tantalum film from beta to alpha crystalline structure was delayed by 100 degrees C and the formation of tantalum carbide was also hindered when ruthenium interlayer is present. X-ray reflectivity measurements indicate that the surface and interfacial area of C/Ta film was maintained to achieve desired magnetic and tribological performance even after N2 annealing at 400 degrees C. In C/Ru/Ta film there is minimum intermixing between tantalum and DLC. In C/Ta film, severe reaction between tantalum and carbon took place. Raman spectroscopy analysis revealed the as-deposited carbon film possessed amorphous structure regardless of the existence of Ru interlayer. Graphitization of carbon film was observed in both structures, upon annealing, however the films with Ru layer was thermodynamically more stable thus desirable in magnetic recording.