Abstract

Previously we reported that when molybdenum is deposited as the top layer of a molybdenum-silicon multilayer mirror, the reflectivity for normal incidence reflection at 130 Å or longer wavelengths decreases with time if the mirror is exposed to air. This effect results from progressive oxidation of the top Mo layer. We have additionally found that the decreased reflectivity is accompanied by strong scattering from the oxide layer, which expands and buckles during the oxidation process. The strong scattering reduces the image contrast and signal/background in imaging experiments using Mo/Si coated optics. However, both the reflectivity degradation and the increased scattering can be reversed by a boiling water etch of the the top surface.

© 1994 Optical Society of America