Cepstral Strain Mapping for Small Pixel-Count Detectors
Authors:
Harikrishnan KP,
Dasol Yoon,
Yu-Tsun Shao,
Zhaslan Baraissov,
Luigi Mele,
Christoph Mitterbauer,
Erik Kieft,
Stefano Vespucci,
David A. Muller
Abstract:
With the decreasing sizes of integrated-circuit components, the semiconductor industry is in growing need of high-throughput strain mapping techniques that offer high precision and spatial resolution, with desired industry goals of 0.01-0.1% and 1 nm respectively. As the fundamental limitation on the measurement precision is set by the Poisson noise, pixel array detectors with high saturation curr…
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With the decreasing sizes of integrated-circuit components, the semiconductor industry is in growing need of high-throughput strain mapping techniques that offer high precision and spatial resolution, with desired industry goals of 0.01-0.1% and 1 nm respectively. As the fundamental limitation on the measurement precision is set by the Poisson noise, pixel array detectors with high saturation current, high dynamic range and fast readout are ideally suited for this purpose. However, due to the limited pixel count on these detectors, they do not work well with traditional strain mapping algorithms that were optimized to work on datasets with a large pixel count. Here, we evaluate the cepstral transform that was designed to address this problem, with the precision determined by the convergence, collection angles and dose while remaining insensitive to the pixel count. We test the performance of our method on silicon wedges and Si-SiGe multilayers, and using datasets collected at different conditions, we show how the measured strain precision scales as a function of dose, aperture size and sample thickness. Using precession gives a further improvement in precision by about 1.5-2x, whereas energy filtering does not have a significant impact on the cepstral method for device-relevant sample thickness ranges.
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Submitted 10 September, 2025;
originally announced September 2025.
Roadmap for Quantum Nanophotonics with Free Electrons
Authors:
F. Javier García de Abajo,
Albert Polman,
Cruz I. Velasco,
Mathieu Kociak,
Luiz H. G. Tizei,
Odile Stéphan,
Sophie Meuret,
Takumi Sannomiya,
Keiichirou Akiba,
Yves Auad,
Armin Feist,
Claus Ropers,
Peter Baum,
John H. Gaida,
Murat Sivis,
Hugo Lourenço-Martins,
Luca Serafini,
Johan Verbeeck,
Beatrice Matilde Ferrari,
Cameron J. R. Duncan,
Maria Giulia Bravi,
Irene Ostroman,
Giovanni Maria Vanacore,
Andrea Konečná,
Nahid Talebi
, et al. (22 additional authors not shown)
Abstract:
Over the past century, continuous advancements in electron microscopy have enabled the synthesis, control, and characterization of high-quality free-electron beams. These probes carry an evanescent electromagnetic field that can drive localized excitations and provide high-resolution information on material structures and their optical responses, currently reaching the sub-ångström and few-meV reg…
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Over the past century, continuous advancements in electron microscopy have enabled the synthesis, control, and characterization of high-quality free-electron beams. These probes carry an evanescent electromagnetic field that can drive localized excitations and provide high-resolution information on material structures and their optical responses, currently reaching the sub-ångström and few-meV regime. Moreover, combining free electrons with pulsed light sources in ultrafast electron microscopy adds temporal resolution in the sub-femtosecond range while offering enhanced control of the electron wave function. Beyond their exceptional capabilities for time-resolved spectromicroscopy, free electrons are emerging as powerful tools in quantum nanophotonics, on par with photons in their ability to carry and transfer quantum information, create entanglement within and with a specimen, and reveal previously inaccessible details on nanoscale quantum phenomena. This Roadmap outlines the current state of this rapidly evolving field, highlights key challenges and opportunities, and discusses future directions through a collection of topical sections prepared by leading experts.
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Submitted 28 May, 2025; v1 submitted 18 March, 2025;
originally announced March 2025.