Exploring the impact of CH₄ gas on crystallization behavior and interfacial structure in Mo/B₄C multilayer films: A novel approach to thin-film engineering

Interface structure and crystallization behavior play an important role in the reflectivity of multilayer mirrors. In this study, Mo/B₄C multilayers were prepared by magnetron sputtering technology with the introduction of CH₄ gases to investigate crystallization behavior, interface diffusion, as well as interface roughness. The results indicate that the introduction of CH₄ gases reduced the crystallinity of the Mo layers to some extent and altered the phase composition. All samples possessed a well-defined periodic structure. The Mo layer was primarily in a microcrystalline or amorphous state, thereby effectively reducing the interface roughness of the multilayer film. Additionally, with the introduction of CH₄ gases, an interlayer of molybdenum carbide was formed at the B₄C-on-Mo interface, effectively preventing interface diffusion between the layers.