Investigation of reflectance of molybdenum Silicon (mo/si) multilayer thin film coating on sio2 Substrate in the extreme ultra-violet and soft X-ray electromagnetic spectrum range

Abstract

In the electromagnetic spectrum, extreme ultraviolet (EUV) and soft x-ray radiation is found between UV light and hard x-rays. Photons of this spectral region have very small absorption lengths in all kinds of material due to the strong interaction with matter. The transmission, reflection and absorption measurement techniques are evolving continuously strengthened by innovations of numerical optimization methods and improving measurement accuracies. As a result, the widely designing thin films and multilayers for many fundamental and technological applications are used. At the same time, the limitation of the methods have been identified when it comes to EUV and soft X-rays. This thesis is to investigate the reflectance of Mo/Si multilayers thin film with the help of Fresnel equations using “IMD; software package for modeling the optical properties of multilayer thin films”. The reflectance of Mo/Si multilayer thin film was performed as function of the film thickness ratio, roughness of the film and grazing incidence angle. The reflectance of Mo/Si multilayer thin film with respect to thickness film ratio is achieved for Γ=0.4 as the peak value of 67% at λ=136.5 ˚ A. The reflectance of Mo/Si multilayer thin film with respect to roughness interface of the film on grazing incidence angle is exponentially decreases with increasing roughness of the film. And as the wave length gets shorter the reflectance of the multilayer thin film decreases. The computed values of reflectance of Mo/Si multilayer as the function of grazing incidence angle shows that the reflectance achieve the first Bragg peaks is 76.4%. The reflection is concentrated in the peaks according to the Bragg law, at larger angle than Mo and Si critical angles