Investigation of the amorphous-to-crystalline transition in Mo/Si multilayers

The microstructure of Mo/Si multilayers grown by magnetron and ion beam sputter deposition has been characterized over a range of Mo layer thicknesses. We observe an abrupt amorphous-to-crystalline transition in the Mo layers at a thickness of ∼2 nm. The transition exhibits several interesting features including a large decrease in the thickness of the Si-on-Mo interlayer and a significant increase in the roughness of the multilayer. We present an explanation for the transition behavior in terms of a critical thickness for the nucleation of Mo crystallites.