Influence of Crystal Defects on the Reflectivity of the Aluminum

Abstract

The effect of ion-assisted deposition of the Al films on their UV reflectance is investigated in this paper. The films' reflectance is measured by a spectrophotometer. The obtained films are examined by using transmission electron microscopy (TEM), X-ray diffraction analysis (XRD), and atomic force microscopy (AFM). The TEM and AFM measurements allow the determination of the size of crystallites in a film and its microstructure. The XRD analysis reveals that the films deposited with argon ion-beam assist are characterized by much higher microstress levels compared to the films deposited without ion assist. The comparison of the Al films’ reflectance measurements indicate that the films with a higher microstress level (hence, higher defect concentration) are characterized by the enhanced reflectance in the UV region. The conducted investigation shows that the defects of the Al films’ crystalline structure affect its optical properties.