Monitoring Variations in Crystalline Structure at the Surface of Thick Pd2Si Films With Variable Angle Spectroscopic Ellipsometry

Published

October 12, 2021

Author(s)

E Mirowski, S R. Leone

Abstract

Two films of palladium silicide (1000 ), one single crystalline and one partly polycrystalline with smaller crystallites at the surface,are investigated using variable angle spectroscopic ellipsometry. Analysis is carried out in the 200 nm (6.2 eV) to 1100 nm (1.1 eV) wavelength range at angles of 65 , 70 , 75 and 80 with respect to the surface normal. The optical parameters, the index of refraction (n) and the emissivity (k), as well as the corresponding real (ε₁) and imaginary (ε₂) parts of the dielectric function differ for the crystalline and partly polycrystalline films. At the 70 angle of incidence, we fit the data using a Lorentzian oscillator model consisting of five oscillators. A major transition in the Pd₂Si enegy band diagram, at 2.5 eV, is represented by one of the oscillators. For the crystalline sample, the amplitude, broadening and central energy of this oscillator are 54.28 3.05 eV², 1.145 0.028 eV and 2.50 0.01 eV, respectively. In contrast, the broadening parameter for the partly polycrystalline sample is 1.334 0.025 eV. Since the angles of incidence, 65 and 80 , correspond to probe depths of approximately 100 and 40 , respectively, we identify the presence of optical anisotropy as a function of depth within the sample and compare this for the single crystalline and polycrystalline films.

Citation

Applied Surface Science

Pub Type

Journals

Keywords

pd₂Si, surface optical properties

Citation

Mirowski, E. and Leone, S. (2021), Monitoring Variations in Crystalline Structure at the Surface of Thick Pd₂Si Films With Variable Angle Spectroscopic Ellipsometry, Applied Surface Science (Accessed April 18, 2024)