Structural and electrical properties in tungsten/tungsten oxide multilayers

• W/WO3 multilayers with nanometric periods are produced by gas pulsing.
• Multilayers are mainly amorphous and the oxide sub-layers composed of WO3.
• Crystallized inclusions of β-W and β-W3O phases in metallic sub-layers
• Metallic-like behavior with low temperature coefficient of resistance

Tungsten and tungsten oxide periodic nanometric multilayers have been deposited by DC reactive sputtering using the reactive gas pulsing process. Different pulsing periods have been used for each deposition to produce metal-oxide periodic alternations ranging from 3.3 to 71.5 nm. The morphology, crystallinity and chemical composition of these films have been investigated by transmission electron microscopy and energy-dispersive X-ray spectroscopy techniques. The produced multilayers exhibited an amorphous structure and the composition stability of WO3 sub-layers has been pointed out. Moreover, electrical properties have also been studied by the van der Pauw technique. It revealed a clear stability of resistivity versus temperature for almost all samples and an influence of the multilayered structure on the resistivity behavior.