Abstract

A nonlinear, least-squares curve-fitting method is described that simultaneously determines the optical constants and the thickness of a very thin (≲ 100-Å) film from reflectance versus angle of incidence (R − θ) data measured in the soft-x-ray region. The method is applied to R − θ data obtained for very thin, sputtered films of carbon (65 Å thick) and gold (94 Å thick) at photon energies of 60–900 eV. The results show that the present method is capable of accurately determining the thickness of very thin films even for transparent materials, and that the obtained optical constants are in good agreement with values reported for films with a thickness of 1000 Å.

© 1994 Optical Society of America

Optical constants of very thin gold films in the soft x-ray region

Mihiro Yanagihara, Jianlin Cao, Masaki Yamamoto, Akira Arai, Shigeru Nakayama, Tamaki Mizuide, and Takeshi Namioka
Appl. Opt. 30(19) 2807-2814 (1991)

Optical constants of gold in the soft-x-ray region from reflection and transmission measurements

R. Wolf, H.-G. Birken, C. Blessing, and C. Kunz
Appl. Opt. 33(13) 2683-2694 (1994)

Determination of thickness and optical constants of thin films from photometric and ellipsometric measurements

Eduardo Elizalde, Jean Marc Frigerio, and Josette Rivory
Appl. Opt. 25(24) 4557-4561 (1986)

Reflectance measurements on clean surfaces for the determination of optical constants of silicon in the extreme ultraviolet–soft-x-ray region

Regina Soufli and Eric M. Gullikson
Appl. Opt. 36(22) 5499-5507 (1997)

Optical constants of float glass, nickel, and carbon from soft-x-ray reflectivity measurements

I. Diel, J. Friedrich, C. Kunz, S. Di Fonzo, B. R. Müller, and W. Jark
Appl. Opt. 36(25) 6376-6382 (1997)