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Applied Optics

Applied Optics


  • Editor: James C. Wyant
  • Vol. 45, Iss. 7 — Mar. 1, 2006
  • pp: 1627–1639

Determination of properties of wedged, nonuniformly thick, and absorbing thin films by using a new numerical method

Jonghoon Baek, Desiderio Kovar, John W. Keto, and Michael F. Becker  »View Author Affiliations

Applied Optics, Vol. 45, Issue 7, pp. 1627-1639 (2006)

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Nonuniformity in the thickness of thin films can severely distort their transmission spectra as compared with those of flat, smooth films. Methods that extract properties such as refractive index, thickness, and extinction coefficient of such films can suffer inaccuracies when they are applied to wedged or nonuniformly thick films. To accurately extract optical properties of nonuniform films, we have developed a novel numerical method and efficient constitutive relations that can determine film properties from just the transmission spectrum for films that are locally smooth with negligible scattering loss. This optimum parameter extraction (OPE) method can accommodate films with two-dimensional thickness variation that would result in significant errors in the values of refractive index and film thickness if not considered. We show that for carefully chosen test cases and for actual pulsed-laser-deposition AlN thin films, properties such as refractive index, extinction coefficient, and film thickness were very accurately determined by using our OPE method. These results are compared with previous techniques to determine the properties of thin films, and the accuracy of and applicable conditions for all these methods are discussed.

© 2006 Optical Society of America

OCIS Codes
(240.0310) Optics at surfaces : Thin films
(310.3840) Thin films : Materials and process characterization
(310.6860) Thin films : Thin films, optical properties

ToC Category:
Optical Interference Coatings

Original Manuscript: May 5, 2005
Revised Manuscript: August 26, 2005
Manuscript Accepted: August 29, 2005

Jonghoon Baek, Desiderio Kovar, John W. Keto, and Michael F. Becker, "Determination of properties of wedged, nonuniformly thick, and absorbing thin films by using a new numerical method," Appl. Opt. 45, 1627-1639 (2006)

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