Using Atomic Layer Deposition Method to Create Antireflective Coatings

Atomic layer deposition (ALD) is a new method in film-forming technology. With many advantages compared to other method, this method allows the creation of coatings of thicknesses less than 10 nm, thereby opens up many new research directions in coatings simulation and fabrication. This article studies the application of ALD in simulation and fabrication of broadband antireflective coatings on optical surfaces. The refractive indices of silicon dioxide and aluminum oxide, which are two materials used to create the antireflective coatings in this study were experimentally determined. A technique to determine the structure of coatings satisfying one or several conditions was also presented in this work. Such coatings may consist of symmetrical or asymmetrical cells, which are created using ALD. Measurement results of the received coatings showed that the reflectance does not exceed 2% in the wavelength range of 420–820 nm. Coatings with asymmetrical structures have lower reflectance than those with symmetric structures. The average measured reflectance of the symmetric and asymmetrical coatings in the range of wavelength 420–820 nm was 1.18% and 0.78%, respectively.