Speaker
Description
The development of superconducting thin films for quantum technologies, cryogenic electronics, and energy-efficient devices requires precise control of atomic-scale structure, chemistry, and interfaces. This contribution demonstrates how advanced transmission electron microscopy (TEM) techniques provide a comprehensive framework for assessing the structural characteristics that govern superconducting performance, such as in adavnced thin-film heterostructures featuring proximity effects. Emphasis is placed on the correlation between atomic-resolution imaging, nanoscale chemical analysis, and interface quality in multilayer systems deposited on technologically relevant substrates.
The presented micrographs illustrate a representative Ti/Al thin-film stack grown on a 4H-SiC substrate. High-resolution TEM reveals a continuous and abrupt Al/Ti interface with well-defined lattice fringes, while the Ti layer exhibits a columnar nanocrystalline morphology extending across the film thickness. Cross-sectional STEM imaging confirms the uniformity of the deposited layers and the conformal coverage over patterned topography. Complementary high-angle annular dark-field (HAADF) imaging and elemental mapping clearly distinguish the spatial distribution of Al, Ti, and Si, demonstrating limited elemental intermixing and excellent compositional integrity throughout the heterostructure. The presence of a thin oxidized Al surface layer, identified during lamella preparation, further highlights the sensitivity of electron microscopy for detecting nanoscale surface modifications that may influence device fabrication and reliability.
These results exemplify the capability of state-of-the-art TEM methodologies to quantify crystalline quality, interface sharpness, grain morphology, oxidation, and chemical homogeneity with nanometer and atomic resolution. Such information is essential for understanding the relationship between microstructure and superconducting properties, including critical temperature, critical current density, and coherence across interfaces. The presented approach establishes advanced electron microscopy as an indispensable characterization platform for the design, optimization, and reliability assessment of next-generation superconducting thin films and hybrid quantum materials.