Inhibition of chemical interaction of molybdenum and silicon in a Mo/Si multilayer structure by the formation of intermediate compounds

Abstract

In the present study, the formation of intermediate compounds in the Mo/Si multilayer was realized by the introduction of barrier layers at the interfaces. Their impact on the interdiffusion of Mo and Si was analyzed via X-ray photoelectron spectroscopy. It was established that the insertion of a thin Be barrier layer led to the formation of beryllide MoBe₁₂ at the interface Si-on-Mo, which prevented the formation of molybdenum disilicide and improved the interface. The insertion of the B₄C barrier layer led to its complete decomposition with the formation of borides and carbides of molybdenum and silicon (MoB_x, SiB_x, Mo_xC and SiC_x) at the Si-on-Mo interface. The formation of only MoB_x and SiC_x was detected at the Mo-on-Si interface. It was important that the insertion of a thin B₄C barrier layer did not fully prevent the formation of MoSi₂ at both (Si-on-Mo and Mo-on-Si) the interfaces. These facts allowed us to assume that the diffusion barrier function of the B₄C interlayer could be caused by the stability of the formed compounds, rather than the stability of the B₄C layer itself.