EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

As the need for reliable 3D-printing at the nanoscale is rapidly increasing, appropriate methods have to be developed to push their capabilities beyond former limitations. In the small pool of capable techniques, Focused Electron Beam Induced Deposition (FEBID) is a promising candidate, as it enables the mask-less, direct-write fabrication of freestanding 3D nano-architectures with a high flexibility concerning design, material and functionality. This technology relies on the local decomposition of surface adsorbed precursor molecules by a focused electron beam. As the latter is constant, one can rationalize that the local precursor coverages determine incremental growth rates and thus predictability, precision and reliability. Recently, it was found that local heating by the electron beam itself can impact the precursors residence time at the growth front, which changes the effective coverage up to a point, where further growth becomes unstable. Based on those insights, we here turn around the situation and lower the substrate temperature to study the implications on growth stability and fabrication precision. In more detail, we use 3D multi-pod designs and study growth dynamics (growth rates), morphological peculiarities (structural dimensions, branch bending), internal structure (transmission electron microscopy) and chemical composition (energy dispersive X-ray spectroscopy) for a temperature range of 5 °C to 30 °C. In a second step, we vary the leg numbers of the multi-pods and demonstrate the implications on growth rates and advanced patterning procedures. The results show that lowering the temperature boosts the growth efficiencies by a factor up to 3.8 without losing 3D precision, while at the same time, the unique metal-matrix composition is maintained. A discussion about implications on mechanical and electrical properties round up the study, which is concluded by a brief explanation of the homemade Peltier stage.