Optical constants of e-beam-deposited zirconium dioxide measured in the 55–150 Å wavelength region using the reflectivity technique

In the present study, optical constants of e-beam-deposited zirconium dioxide (ZrO2) thin film are determined in the 55–150 A soft x-ray wavelength region using the angle-dependent reflectivity technique. Soft x-ray reflectivity measurements are carried out using the reflectivity beamline at the Indus-1 synchrotron radiation source. Derived optical constants (δ and β) are compared with the tabulated values of Henke et al. [http://henke.lbl.gov/optical_constants/asf.html]. It is found that the measured δ values are consistently lower than the tabulated bulk values in the 70–150 A wavelength region. In this region, the delta values are lower by 19%–24% from the tabulated data. Below the Zr M4 edge (66.3 A), a deviation in delta values is found as ∼2%–21%. These changes are attributed to growth-related defects (oxygen and voids) and variation in film stoichiometry. To the best of our knowledge, the present study gives the first reported experimental values of optical constants for ZrO2 in the 55–150 A wavelength region.