Grazing incidence X-ray diffraction analysis of alkali fluoride thin films for optical devices

• Published in: Thin solid films Vol. 333; no. 1; pp. 157 - 164
• Main Authors: Cremona, M., Mauricio, M.H.P., Fehlberg, L.V., Nunes, R.A., Scavarda do Carmo, L.C., de Avillez, R.R., Caride, A.O.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 23.11.1998; Elsevier Science
• Subjects: Alkali halides; Condensed matter: structure, mechanical and thermal properties; Exact sciences and technology; Mechanical and acoustical properties; Optical device; Physical properties of thin films, nonelectronic; Physics; Residual stress; Structure and morphology; thickness; Surfaces and interfaces; thin films and whiskers (structure and nonelectronic properties); Thin film structure and morphology; X-ray diffraction; X-ray diffraction; Alkali halides; Optical device; Residual stress; Inorganic compounds; Grazing incidence; Polycrystals; Binary compounds; Lithium fluorides; Residual stresses; XRD; Experimental study; Lattice parameters; Optical waveguides; Thin films; Multilayers; Luminescent devices; Physical vapor deposition; Alkali metals Fluorides; Sodium fluorides
• ISSN: 0040-6090; 1879-2731
• DOI: 10.1016/S0040-6090(98)00849-9

Alkali fluoride multilayered thin films are promising systems for different optical applications, including light generation and waveguide. Despite this, some of their physical properties are still not well known. The mechanical behaviour of these materials, when evaporated in the form of thin films, plays a fundamental role for the success of the related optoelectronic device. In this work, LiF, NaF and LiF/NaF polycrystalline thin films were deposited onto different substrates at temperatures varying from 50 to 200°C by physical vapour deposition (PVD). Using the X-ray diffraction technique with grazing incidence geometry (GIXRD), the residual stresses and the microstrains present in films deposited in different experimental conditions were measured. The lattice parameters and the mean domain were also estimated. The results show the dependence of the residual stresses in the films upon the cooling rate and the type of substrates and give, for the first time, an order of magnitude of these quantities for such systems.