CrB2 diffusion barriers for Mo/Si multilayer structures

Properties of CrB2 thin diffusion layers sputtered in Mo/Si multilayer structures and their effect on the x-ray/EUV reflectance are reported. A special attention is paid to determine a critical thickness t* for barrier layers where they isolate parent layers of Mo and Si completely and to reveal the degree of interaction of the barrier material with parent materials. A dependence of t* on the deposition rate of CrB2 is found. CrSi2 and B3Si are established as the most probable phases formed in the barrier layers. The diffusion coefficients and temperature during formation of CrB2 are estimated. The use of thin CrB2 barriers is shown to be profitable in a fabrication of the EUV mirrors with enhanced reflectivity.