Optical constant measurements of the uppermost layer of a reflection multilayer using reflection and total electron yield spectra

Abstract

Total electron yield (TEY) is a method for obtaining optical constants by measuring the angle dependence of the yield intensity in the soft X-ray region [S. V. Pepper, J. Opt. Soc. Am. 60, 805 (1970)]. In this study, previous methods are extended by rewriting the previous formulae of yield intensity: the intensity was directly related to a reflectance and phase value corresponding to both the thickness of the uppermost layer and the reflection phase. Phase values obtained practically from the reflection and TEY measurements were found to change in accordance with increases in the thickness of the uppermost Mo layer. Refractive indices were derived from the phase differences between the two different phase values corresponding to the variation in the uppermost Mo layer. Practical study showed that the refractive indices of the uppermost Mo layer are close to those of MoO 2 .