Optimization of the silicon oxide layer thicknesses inserted in the Mo/Si multilayer interfaces for high heat stability and high reflectivity

摘要

We previously demonstrated that the introduction of silicon oxide (SiO_(2)) layers into the interfaces of the Mo/Si multilayer was quite effective in improving the heat stability of the multilayer M. Ishino et al., Surf. Coat Technol. (to be published). However, the soft x-ray reflectivity of the Mo/Si multilayer with SiO_(2) layers decreased with the thickness of the SiO_(2) layer because of the large absorption of x rays by oxygen. In this article, an optimization of the thicknesses of the SiO_(2) layers inserted in the Mo/Si multilayer has been performed so as to minimize the decrease in the soft x-ray reflectivity with the high heat stability maintained. An asymmetric SiO_(2) layer thicknesses of 0.5 and 1.5 nm are found to be most favorable at the Si-on-Mo interface and at the Mo-on-Si interface, respectively.