Effect of the target shuttering on the characteristics of the Ta-Si-N thin films by reactive magnetron co-sputtering

摘要

The Ta-Si-N thin films were prepared using a reactive magnetron co-sputtering with and without an alternating target shutter control at different N-2 flow ratios (FN2% = FN2/(FAr + FN2) x 100%) of 3-20%. The evolution of microstructure, composition, morphology, resistivity, and nanomechanical properties of Ta-Si-N films was characterized by X-ray diffraction (XRD), energy dispersive X-ray spectrum (EDS), scanning electronic microscopy, four-point probe technique and nanoindentation, respectively. The broad XRD peaks of Ta-Si-N films with and without target shuttering at low 3-10 FN2% showed the microstructure was quasi-amorphous i.e. nanocrystalline grains embedded in an amorphous matrix. The quasi-amorphous Ta-Si-N without target shuttering was transformed into the polycrystalline phase at 20 FN2% while that with target shuttering still remained in quasi-amorphous microstructure due to the increased Si content. The resistivity of quasi-amorphous Ta-Si-N films with and without target shuttering at 3-10 FN2% ranged in 262-385 mu Omega cm while that of Ta-Si-N films at 20 FN2% was much higher at 976-9925 mu Omega cm. The hardness of quasi-amorphous Ta-Si-N films with and without target shuttering at 3-10 FN2% ranged from 14.3 to 18.5 GPa while that of polycrystalline Ta-Si-N film was about 10.3 GPa. Quasi-amorphous Ta-Si-N films had much lower resistivity, higher nanohardness and smooth morphology compared to the polycrystalline film.