A technical paper titled “Measuring electrical properties in semiconductor devices by pixelated STEM and off-axis electron holography (or convergent beams vs. plane waves).” was published by researchers at CEA-LETI at the Universite Grenoble Alpes and EPFL.
“We demonstrate the use of both pixelated differential phase contrast (DPC) scanning transmission electron microscopy (STEM) and off-axis electron holography (EH) for the measurement of electric fields and assess the advantages and limitations of each technique when applied to technologically relevant samples. Three different types of samples are examined, firstly a simple highly-doped Si pn junction. Then a SiGe superlattice is examined to evaluate the effects of the mean inner potential on the measured signal. Finally, an InGaN/GaN microwire light-emitting diode (LED) device is examined which has a polarization field, variations of mean inner potential and a wurtzite crystal lattice. We discuss aspects such as spatial resolution and sensitivity, and the concept of pseudo-field is defined. However, the most important point is the need to limit the influence of diffraction contrast to obtain accurate measurements. In this respect, the use of a plane electron wave for EH is clearly beneficial when compared to the use of a convergent beam for pixelated DPC STEM.”
Find the technical paper here. Published January 2024.
David Cooper, Lucas Bruas, Matthew Bryan and Victor Boureau, Measuring electrical properties in semiconductor devices by pixelated STEM and off-axis electron holography (or convergent beams vs. plane waves)., Micron, (2024) doi:https://doi.org/10.1016/j.micron.2024.103594
Further Reading
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Optical and e-beam methods are extended, while new techniques find niche uses.
Metrology Strategies For 2nm Processes
Tools become more specific for Si/SiGe stacks, 3D NAND, and bonded wafer pairs.
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