Focused ion beam (FIB) milling of cross-section specimens for transmission electron microscopy (TEM) produces damage and contamination along the sample surface. Techniques that generate contrast related to electronic sample properties, such as scanning TEM electron beam-induced current (STEM EBIC) imaging, are particularly sensitive and, therefore, susceptible to poor surface quality. This work details a specimen preparation protocol employing Ga FIB preparation followed by Ar ion milling optimized for the surface-sensitive mode of STEM EBIC that measures secondary electron emission. We demonstrate the utility of STEM EBIC for assessing surface quality and mapping electronic properties in advanced devices at high resolution. In samples containing fin field-effect transistors (finFET) structures, STEM EBIC shows noticeable improvements to surface quality with post-FIB Ar ion milling and can clearly distinguish between active and inactive finFETs.

Presentation slides for the ISTFA 2025 Tutorial session “TEM Sample Preparation for Electron Microscopy Characterization and Failure Analysis of Advanced Semiconductor Devices.”

Journal Article Improved Sample Preparation Technique for Transmission Kikuchi Diffraction (TKD) Analyses Allows Large Area Data Acquisition Get access Pawel Nowakowski, Pawel Nowakowski E.A. Fischione Instruments, Inc., Export, PA, USA Search for other works by this author on: Oxford Academic Google Scholar Cecile Bonifacio, Cecile Bonifacio E.A. Fischione Instruments, Inc., Export, PA, USA Search for other works by this author on: Oxford Academic Google Scholar Mary Ray, Mary Ray E.A. Fischione Instruments, Inc., Export, PA, USA Search for other works by this author on: Oxford Academic Google Scholar Paul Fischione Paul Fischione E.A. Fischione Instruments, Inc., Export, PA, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 29, Issue Supplement_1, 1 August 2023, Pages 134–135, https://doi.org/10.1093/micmic/ozad067.060 Published: 22 July 2023

Journal Article Developments in Broad Ion Beam Milling Sample Preparation Instrumentation for Microscopy and Microanalysis Applications Get access Pawel Nowakowski, Pawel Nowakowski E.A. Fischione Instruments, Inc. Export, PA, USA Search for other works by this author on: Oxford Academic Google Scholar Cecile Bonifacio, Cecile Bonifacio E.A. Fischione Instruments, Inc. Export, PA, USA Search for other works by this author on: Oxford Academic Google Scholar Mary Ray, Mary Ray E.A. Fischione Instruments, Inc. Export, PA, USA Search for other works by this author on: Oxford Academic Google Scholar Paul Fischione Paul Fischione E.A. Fischione Instruments, Inc. Export, PA, USA Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 29, Issue Supplement_1, 1 August 2023, Pages 2075–2076, https://doi.org/10.1093/micmic/ozad067.1074 Published: 22 July 2023

The ability to precisely remove the internal structures of a semiconductor device, layer-by-layer, is a necessity for semiconductor research and failure analysis investigation. Currently, numerous techniques are used, such as mechanical polishing, chemical etching, and gas assisted plasma focused ion beam (FIB) milling. However, all of these techniques have limitations in that they are unable to: (1) delayer a millimeter-scale area with nanometer-scale uniformity, (2) rapidly remove thick (>300 nm) device layers, or (3) perform automatic and accurate end pointing, which is challenging on thin (≤300 nm) device layers.

The present work describes application of a method for site-specific plan-view sample preparation for atomic column resolution scanning transmission and transmission electron microscopy (STEM and TEM) from freestanding thin films of multi-phase Al-alloys after laser irradiation induced rapid solidification (RS). The electron-transparent multilayer thin film samples (amorphous Si3N4 substrate plus metal alloy layer) had a total initial thickness of 130-200 nm. At such large total sample thickness frequently multiple grains of the same or different phases overlap along the electron beam path in the RS microstructures of the alloys. Consequently, accurate atomic resolution images in TEM and STEM mode, and composition sensitive analytical data of the metastable microstructural features presenting in the RS microstructures cannot be obtained with confidence. Using low-energy concentrated Ar ion beam milling, locally thinned regions with thickness of 20-30 nm with large fields of view >= (30 mu m)(2) suitable for high-resolution TEM/STEM studies have been created with micron scale site-specificity. As example application, atomic scale resolution TEM/STEM imaging has been performed of the banded grain regions of the RS microstructure established in multi-phase Al-Cu alloy thin films. The sample preparation strategy described here appears to be readily applicable to freestanding thin film specimens in general.

This paper describes developments in instrumentation that allow successful beam-sensitive material sample preparation and its controlled atmosphere transfer to the scanning electron microscope (SEM); we also describe the influence of diverse SEM observation parameters when performing beam-sensitive material microstructural characterizations. To complete accurate and informative SEM analytical studies, the samples must be well-prepared, represent the native microstructure of the study material, and be without oxidation, contamination, or damage induced by preparation. An artifact-free sample preparation technique is critical to better understand and correlate the synthesis, chemistry, and properties of the material. Preparation of beam-sensitive materials, such as lithium or Li-ion batteries, is particularly difficult because these materials are highly sensitive to oxygen, nitrogen, water, and carbon dioxide. They are either a soft material (Li metal) or made from compacted powders (different Li-ion based elements, such as sulfide solid-state electrolyte or Ni-Co-Mn cathode) – both types of materials are easily damaged by mechanical preparation. The material characteristics make sample preparation under ambient atmosphere impossible. However, ion milling-based techniques under controlled environment make Li metal/Li-ion battery sample preparation possible. they conditions during milling transfer to under milling No

In recent years, scanning electron microscopy (SEM) techniques have undergone significant development and expansion in academia and industry. SEM is used for a wide range of applications in the materials science, engineering, and earth science fields. The technique can gather data from large areas (to millimeter scale) and spatial resolution to nanometric scale. However, when using some analytical techniques, such as electron backscatter diffraction (EBSD) or energy dispersive X-ray spectroscopy (EDS), the SEM spatial resolution can be limited to ~100 nm (depending on several parameters, including the accelerating voltage of the microscope and the atomic number of the material) [1]. The spatial resolution limitation is the result of the electron beam volume interaction created in the analyzed material. Putting an electron-transparent specimen into a SEM and conducting analytical scanning transmission electron microscopy (STEM) observation overcomes this problem; the STEM-inSEM technique can offer improved sub-nanometric spatial resolution. Following the development of the STEMin-SEM approach, analytical techniques typically associated with SEM have been adapted to electron-transparent specimens. One example is transmission Kikuchi diffraction (TKD) [2-5]. The TKD technique can offer improved spatial resolution of ~3 to 10 nm, depending on specimen thickness [6], within maximum fields of view in the ~101 to 102 μm2 range [7]. The development of on-axis detectors specific for TKD [5, 8] offer not only crystallographic orientation mapping of an electron-transparent specimens, but also bright field (BF) and dark field (DF) forwardscattered electron imaging possibilities.

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An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

An abstract is not available for this content so a preview has been provided. As you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

This paper presents a development in semiconductor device delayering by broad ion beam milling that offers a uniform delayering area on a millimeter scale. A milling area of this size is made possible by the user's ability to position ion beams individually to cover the desired area. This flexibility in ion beam positioning also enables more precise targeting of an area of interest.

Metal-support interactions significantly affect the performance of heterogeneous catalysts, of which Pt supported on gamma-Al2O3 is one of the most widely used. Characterizing the bonding of Pt on the Pt/gamma-Al2O3 surface is key to fully understanding the catalyst- support interaction. Herein aberration-corrected and monochromated scanning transmission electron microscopy-based electron energy-loss spectroscopy (STEM-EELS) were employed on a model Pt/gamma-Al2O3 (111) catalyst to locally investigate the bonding between Pt and the gamma-Al2O3 support. Differences in the aluminum L-2,L-3-edge and oxygen K-edge EELS near-edge fine structure between spectra acquired at the Pt/gamma-Al2O3 (111) interface and the bulk gamma-Al2O3 served as signatures of the interfacial bonding environment. Fine structure in the interface-localized Al-L-2,L-3 edge suggested a larger fraction of tetrahedrally coordinated AI atoms at the Pt/gamma-Al2O3 (111) interface, which was confirmed by DFT simulations. The interface-localized O -K edge EELS revealed a prepeak associated with several types of oxygen bonding. To determine the specific interfacial O bonding, O-K edge EELS spectra were simulated from an array of Pt/gamma-Al2O3 (111) bonding configuration models. The simulated EELS from the interfacial bonding models revealed an O bonding motif consistent with the experimental O-K edge EELS fine structure.

Journal Article Probing the Cation Distribution in Gamma-alumina Enabled by O-K Edge Artifact Suppression Using Cryo-EELS Get access Henry Ayoola, Henry Ayoola University of Pittsburgh, Pittsburgh, Pennsylvania, United States Search for other works by this author on: Oxford Academic Google Scholar Cheng-Han Li, Cheng-Han Li The Ohio State University, Columbus, Ohio, United States Search for other works by this author on: Oxford Academic Google Scholar Stephen House, Stephen House University of Pittsburgh, Pittsburgh, Pennsylvania, United States Search for other works by this author on: Oxford Academic Google Scholar Joshua Kas, Joshua Kas University of Washington, Seattle, Washington, United States Search for other works by this author on: Oxford Academic Google Scholar John Rehr, John Rehr University of Washington, Seattle, Washington, United States Search for other works by this author on: Oxford Academic Google Scholar Joerg Jinschek, Joerg Jinschek The Ohio State University, Columbus, Ohio, United States Search for other works by this author on: Oxford Academic Google Scholar Wissam Saidi, Wissam Saidi University of Pittsburgh, Pittsburgh, Pennsylvania, United States Search for other works by this author on: Oxford Academic Google Scholar Judith Yang, Judith Yang University of Pittsburgh, Pittsburgh, Pennsylvania, United States Search for other works by this author on: Oxford Academic Google Scholar Cecile Bonifacio Cecile Bonifacio E.A. Fischione Instruments, Inc., Export, Pennsylvania, United States Search for other works by this author on: Oxford Academic Google Scholar Microscopy and Microanalysis, Volume 26, Issue S2, 1 August 2020, Pages 2550–2552, https://doi.org/10.1017/S1431927620021996 Published: 01 August 2020

Gamma-alumina (γ-Al2O3), like other low-Z oxides, is readily damaged when exposed to an electron beam. This typically results in the formation of a characteristic pre-edge peak in the oxygen-K edge of electron energy-loss spectra (EELS) acquired during or after the damage process. This artifact can mask the presence of intrinsic O-K edge fine structure that would reveal chemical properties of the material; therefore, its suppression is key. In this work, we systematically investigate the conditions that give rise to the damage-induced O-K pre-edge peak and show that it can be effectively suppressed by performing EELS experiments at cryogenic (cryo) temperatures. Prolonged exposure of γ-Al2O3 to a focused electron beam results in a hole bored through the sample; this was used as a reproducible beam damage condition. O-K edge EELS spectra were collected from a single-crystal γ-Al2O3 sample both during and after focused electron beam hole drilling, and at room and cryo temperatures, using a monochromated scanning transmission electron microscope (STEM). The characteristic 531 eV pre-edge peak visible in the room temperature EELS spectra was completely suppressed in the cryo-EELS spectra, even in the presence of a visible drilled hole. We then correlated these experimental observations with multiple-scattering EELS simulations to determine the likely atomistic origin of the damage-induced O-K pre-edge peak. The findings indicate that the pre-edge peak is caused primarily by the presence of surface O-O bonds formed during beam damage, and that operating at cryo temperature suppresses the formation of surface O-O bonds, thus preventing formation of the O-K pre-edge peak. Additionally, Al-L2,3 edge EELS spectra revealed Al loss primarily from tetrahedral sites during hole drilling.

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