Depth analysis of Al/ZrC interfaces using SIMS and x-ray reflectivity

The Al/ZrC/Al/W multilayer structure is suitable for waveguide applications in the hard x-ray range in order to confine the wave field in a nanometer-thick layer. Intermixing of Al at the interfaces is a serious problem to achieve the expected performances from an experimentally grown multilayer. In the present study, our aim is to investigate the effect of a capping layer on the ZrC/Al interfaces in an C/Al/ZrC/Al/W waveguide structure. We use time of flight secondary ion mass spectrometry (ToF-SIMS) and soft x-ray reflectivity (SXR) to study the x-ray waveguide structure. Structural parameters of the stack, density, thickness and roughness of the layers, are determined through fitting of SXR data. SIMS results indicate that the Al diffusion towards the top of the stack is responsible of the formation of wide and asymmetric interfaces in the waveguide structure.