Optical properties of sputtered amorphous beryllium nitride thin films Available to Purchase

The optical properties of amorphous beryllium nitride $(a-Be3N2)$ thin films deposited on Si (100) at temperature $<50°C$ using reactive rf sputtering deposition were examined in the wavelength range of $280–1600nm$⁠. X-ray diffraction of the films showed no structure, suggesting the $Be3N2$ films grown on the Si (100) substrates are amorphous. The thicknesses and optical constants of the films were derived from variable-angle spectroscopic ellipsometry measurements using the Cauchy-Urbach model. Refractive indices and extinction coefficients of the films were determined to be in the range $n=1.98–2.28$ and $κ=0.0002–0.08$⁠, respectively. Analysis of the absorption coefficient shows the optical absorption edge of $a-Be3N2$ films to be $4.12±0.01eV$⁠. These values were in excellent agreement with the photoluminescence measurements $(4.18eV)$⁠. The surface morphology was characterized by atomic force microscopy. The surfaces of the films were very smooth and their average roughnesses were measured to be in the range of $0.36–2.4nm$⁠. An effective medium approximation model of 50% $Be3N2$ and 50% voids was used in the ellipsometric fitting procedure. The spectral dependence of transmissivity of the films was investigated at different angles of incidence (20°–80°). The $a-Be3N2$ films shown high transmissivity (80%–99%) in the visible and near infrared regions.