Influence of Increasing Density of Microstructures on the Self-Propagating Reaction of Al/Ni Reactive Nanoscale Multilayers

Surface structuring methods are crucial in semiconductor manufacturing, as they enable the creation of intricate structures on the semiconductor surface, influencing the material's electrical, mechanical, and chemical properties. Herein, one such structuring method known as reactive ion etching to create black Si structures on silicon substrates is employed. After thermal oxidation, their influence on the reaction of Al/Ni nanoscale multilayers is studied. It reveals distinct reactive behaviors without corresponding differences in energy release during differential scanning calorimetry measurements. Higher oxidized black Si structure densities result in elevated temperatures and faster reaction propagation, showing fewer defects and reduced layer connections in cross-sectional analyses. The properties of the reactive multilayers (RML) on high structure density show the same performance as a reaction on flat thermal SiO2, causing delamination when exceeding 23 structures per mu m2. Conversely, lower structure density ensures attachment of RML to the substrate due to an increased number of defects, acting as predetermined breaking points for the AlNi alloy. By establishing the adhesion between the reacted multilayer and the substrate, surface structuring could lead to a potential increase in bond strength when using RML for bonding. Al/Ni reactive multilayers (RML) are sputtered on different densities of oxidized black Si structures and then ignited by spark ignition. Cross-section analysis demonstrated differences in the area covered by defects/voids in the RML. Lower structure density leads to less defects and better adhesion of the RML.image (c) 2024 WILEY-VCH GmbH