Optical Constant Determination of Thin Films Condensed on Transmitting and Reflecting Substrates
Abstract
In this report, a new subtractive Kramers-Kronig computer program is described which can obtain accurate optical constants of a uniform thin film on a thick substrate using only the transmittance measurements of a single-film thickness. Preliminary results from existing data show that the optical properties of a dielectric film may depend, to a small degree, upon the thickness of the film. This effect seems to be more noticeable in films containing molecules, such as H2O and NH3, which readily form hydrogen bonds. Also described are two methods for extracting the optical constants of a dielectric thin film from measurements of the reflectance of a beam incident in a vacuum upon a film layer on a metal substrate. In one method, the dependence is observed of the reflectances of several thicknesses of the same film material upon its thickness. This method contains the assumption that the optical properties of a film material do not vary with changes in film thickness. The second method does not depend on this assumption. It uses the reflectance spectrum of a single-film thickness to compute the optical constants of the film from a dispersion relation.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 01, 1984
- Accession Number
- ADA140845
Entities
People
- K. F. Palmer
- M. Z. Williams
Organizations
- Arnold Engineering Development Complex