The optical constants determination of thin-films

Yıl 2015, Cilt: 36 Sayı: 3, 721 - 728, 13.05.2015

A. Sardarzaeı Z. Kıamehr

Öz

Abstract. A method for calculating the optical constants of weakly absorbing homogeneous thin films of refractive index, n lower than substrate index, s (s < n) and extinction coefficient, k from the spectral Transmission information alone with no prior knowledge of their characteristics was studied. Initially the procedure uses transmission turning point data to estimate the refractive index, n and extinction coefficient, k by an analytical approach. The calculations are done from the knowledge of transmission turning point data, which was obtained from Shimadzu UV3100 spectrophotometer. The data are then fitted to a high order polynomial function that undergoes an iterative refinement routine by means of a goal seek routine to determine with good accuracy the film parameters as a function of wavelength.

Anahtar Kelimeler

optical constants, refractive index, transmission, thin films, turning point and weakly absorbing

Kaynakça

• Meredith, P. (1992), “Linear and non-linear optical properties of molecular beam deposited thin films and devices”, Theses collection, Heriot-watt university, Chapter 1, 2 and 3, PP 1-119. [2] Valeev, A. S. (1963), “Determination of the optical constants of weakly absorbing thin films”, Opt. Spectrosc., (USSR), 15, PP 269-274.
• Lyashenko, S. P. and Moloslavskii, V. K. (1964), “A simple method for the determination of thickness and optical constants of semi-conducting and dielectric layers”, Opt. Spectrosc., (USSR), 16, PP 80-81.
• Manifacier, J. C. Gasiot, J. and. Fillard, J. P. (1976), “A simple method for the determination of the optical constants n, k and the thickness of a weakly absorbing thin film”, J. Phys. E: Sci. Instrum, 9, PP 1002-1004.
• Swanepoel, R. (1983), “Determination of the thickness and optical constants of amorphous silicon”, J.Phys. E: Sci. Instrum., 16, PP 1214-1222.
• Bennett, J. M. and Booty, M. J. (1966), “Computational method for determining n and k for a thin film from measured reflectance, transmittance and film thickness”, Appl. Opt., 5, PP 41-43. [7] Dobrowolski, J. A. Ho, F. C. and Waldorf, A. (1983), “Determination of optical constants of thin film coating materials based on inverse synthesis”, Appl. Opt., 20, PP 3191-3200.
• Walker, A. C. Buller, G. S. and Meredith, P. (1993), “Improved method for determining the optical constants of thin film and its application to molecular beam deposited polycrystalline layers”, App. Opt, 32, PP 5619-5627.