Material characterization and nanohardness measurement of nanostructured Ta–Si–N film

This paper presents a study of the relation between the process, composition and nanohardness of the nanostructured Ta–Si–N films that have been applied in an IC diffusion barrier or mechanical coating. Ta–Si–N films are reactively cosputtered by individual Ta and Si targets in a N2/Ar gas. They are characterized by Rutherford Backscattering Spectroscopy (RBS), grazing incident-angle X-ray diffractometer (GIAXRD) and nanoindenter for the composition, structure and nanohardness analysis, respectively. Increasing Si target power or decreasing Ta target power will produce higher Si/Ta composition ratio in Ta–Si–N films with higher amorphous content as well as smaller nanocrystalline grains. The nanohardness of Ta–Si–N films measured by nanoindentation is between 13.5 and 16.4 GPa. Increasing N2 flow reduces the nanohardness while the grain size of Ta–Si–N film increases slightly. However, increasing Si composition reduces both grain size and nanohardness of Ta–Si–N films.