Investigation On Fabrication And Measurement Of W/B₄C Multilayers

In soft X-ray and X-ray regions, multilayer mirrors were widely used in the applications of synchrotron radiation and astronomical observation, etc. In this thesis, the fabrication and characterization of W/B₄C multilayers mirrors working in X-ray region were studied in detailed. Firstly, the theoretical reflectivities of periodical W/B4C multilayers mirrors were accurately calculated by using the principle of Fresnel reflection and Real-Structure interface roughness model. These W/B4C multilayers were designed for Cu Kαline (0.154nm). According to the calculated results, the function between peak reflectivity and layers number of multilayers could be given. And a method was proposed to optimize the bi-layer number of multilayer. Then, these multilayers with different bi-layer number were fabricated by the direct current (DC) magnetron sputtering system. After fabrication, the reflective performances of these multilayer mirrors were measured by X-ray diffractometer (XRD) working at Cu Kαline. The measured results coincide with the theoretical calculations. In order to verify the theory of the interface roughness of W/B4C multilayers varying with its bi-layer number, the interface roughness of about the top 100 bi-layers were characterized by using the X-ray scattering measurement method. The measured results indicate that the interface roughness of multilayer increase with bi-layer number, and provide the experimental support to the Real-Structure model. So, using this model, the real interface roughness of W/B4C multilayers can be simulated, and the reflectivity of W/B4C multilayers can also be calculated accurately.