Ellipsometric study of a-Be 3N 2 thin films prepared by radio frequency magnetron sputtering

Abstract

The ellipsometric characterizations of amorphous beryllium nitride (a-Be 3N 2) thin films deposited on Si (1 0 0) and quartz at temperature <50 °C using reactive RF sputtering deposition were examined in the wavelength range 280–1600 nm. X-ray diffraction of the films showed no structure, suggesting the Be 3N 2 films grown on the substrates are amorphous. The composition and chemical structures of the amorphous thin films were determined by using electron spectroscopy for chemical analysis. The surface morphology of a-Be 3N 2 was characterized by atomic force microscopy. The thicknesses and optical constants of the films were derived from spectroscopic ellipsometry measurements. The variation of the optical constants with thickness of the deposited films has been investigated. From the angle dependence of the polarized reflectivity we deduced a Brewster angle of 64°. At any angle of incidence, the a-Be 3N 2 shown high transmissivity (80–99%) and low reflectivity (<18%) in the visible and near infrared regions. Hence, the a-Be 3N 2 could be a good candidate for antireflection optical coatings under conditions of optimized the type of polarization and the angle of incidence.