Antiferroelectric PbSnO3 epitaxial thin films
Advanced Science
2022
Semiconductor Materials & Devices
Common challenges
Semiconductor devices are increasing in complexity as performance requirements become more demanding and new manufacturing processes become available. Many semiconductor devices have intricate 3-dimensional structures with precise nanometer-scale feature sizes, along with more complicated chemistries.
While researchers focus an enormous amount of effort on the fabrication and characterization of these materials, integration of these materials into new products and their subsequent industrialization continues to be a challenge. These challenges commonly affect the precision of a required process and repeatable yield of devices as they are industrialized. Useful information to prevent or mitigate these challenges include:
- Atomic composition of material or device
- Influence on transistor device control
- Chemical properties
- Robustness and ease of analysis to deliver clear insight into material properties
Innovative techniques
To adequately characterize and understand semiconductor materials or devices, you must first ensure each specimen is of the highest quality to resolve critical material structure features. Once prepared, several techniques are available to better understand material complexities and failures to improve device performance.
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Atomic resolution chemical and compositional analysis.
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Family of imaging techniques to enhance, map and quantify elements and chemicals in an image with nanometer resolution.
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Systematic method to generate a spatially resolved distribution of EELS data.
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Award winning, high resolution imaging tools help you to understand material growth, devices ultrastructure and failures.
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Real-time observation of growth processes, chemical reactions and oxidation, irradiation effects, mechanical, magnetic, and ferroelectric properties.
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Specimen preparation
High-performance tools to cut, etch, polish and freeze samples for your unique SEM, TEM or STEM application.
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Useful to elucidate elemental or chemical characterization of a sample.
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Helps you examine crystallographic orientation or texture of materials.
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Visit light emitting materials and devices or batteries and energy storage to learn more about related applications.
Enabling results
Specimen Preparation Imaging & Structure Analysis Composition Analysis Data Analysis
Careful electron microscopy analysis of semiconductor devices begins with proper specimen preparation. Broad ion beam polishing techniques can prepare specimens for both Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) analysis. Studying particular interfaces or structural features in the SEM can be done either in cross-section or by delayering the device to reveal key features over a wide area. The Ilion II and PECS II tools can be used to prepare high-quality surfaces for either cross-section or planar polished specimens and enable excellent imaging, EDS, or EBSD analysis.
Focused-ion beam (FIB) preparation is a commonly used technique for TEM specimen preparation in order to study device features at the nanoscale or atomic scale. However, it can be challenging to achieve the final specimen quality needed to get the best imaging and chemical analysis data. The final speicmen preparation and surface cleaning of a FIB lamella can instead be done with the PIPS II to achieve improved results with less time on the FIB system.
Application: Argon ion polishing of focused ion beam specimens in PIPS II system
Key features of the PIPS II system – including focused ion beams at low energies (~1 mm in diameter), an X,Y alignment stage, an optical camera along with DigitalMicrograph® imaging software, stationary milling, and custom milling angles – make it possible to polish FIB specimens efficiently at <300 eV. Using the PIPS II as the last step in the FIB preparation process improves the specimen quality and removes re-deposited material.
The feature sizes of interest in many semiconducting devices are often on the few-nanometer scale, and require TEM imaging for proper analysis. Gatan’s line of imaging products uniquely addresses many of the challenges that microscopists in the semiconductor industry face.
Flexible, High-Resolution Imaging
Rapid, high-quality TEM imaging is easily done with Gatan's CMOS cameras thanks to their high-resolution detectors (up to 4k x 4k pixels) with “live” imaging, real-time drift correction, and high dynamic range for both imaging and diffraction experiments. Microscopists who need to image their semiconductor devices at a particular orientation can take advantage of the TruAlign option on Gatan's cameras, which allows them to manually rotate the camera image of their sample or quickly align the camera image to a known feature while imaging the sample on the TEM. This makes the interpretation of complex materials stacks or multiple samples more straightforward, without additional time needed for image processing later on. The vide
Low-distortion imaging
Some TEM imaging characterization requires accurate repeated measurements of critical dimensions or features in a specimen over a large field of view or area. These types of imaging studies are improved by the OneView LD camera which guarantees high-resolution, low-distortion (LD) images for quantitative spatial measurements on the TEM. As a result, microscopists have a greater margin to achieve total distortion specifications for regular TEM qualification, and sample qualification can occur more rapidly.
Diffraction Analysis
Gatan's imaging cameras also support 4D STEM techniques for virtual imaging, orientation mapping, strain mapping, and differential phase contrast (DPC). Rapid 4D STEM data collection and analysis routines are built into GMS 3, making it possible for microscopists of all experience levels to carry out 4D STEM experiments. Visit the 4D STEM techniques page for several resources and tutorials on 4D STEM.
Application: Electric field mapping in 2D heterostructures using differential phase contrast
The combination of electrical biasing and 4D STEM DPC made it possible to explore how the electrostatic profile in a heterostructure of MoS2/hBN evolves when subjected to an external electric field.
Electron Energy Loss Spectroscopy (EELS), Energy Dispersive X-Ray Spectroscopy (EDS), and Energy-filtered TEM (EFTEM) are all excellent techniques for determining the composition of crucial regions within a sample along with the elemental distribution. Gatan has a full line of products for composition analysis in the TEM with the GIF Continuum for EELS and EFTEM and the EDAX EDS Powered by Gatan system for EDS.
Visit EELS.info for more information on the theory, experimental setup, and data collection and analysis for EELS and EFTEM.
EELS
Collecting EELS data from semiconductor devices is faster and easier than ever thanks to improvements in the speed and sensitivity of the latest Gatan spectrometers. Features like DualEELS and live mapping make the data collection process simpler while providing real-time feedback to the user during data collection.
The advances in direct detection camera technology can be paired with EELS spectrometers to improve the energy resolution and sensitivity of the system. As a result, weak signals and more detailed fine structure can be resolved with EELS analysis. Low-dose techniques and in-situ techniques can then also be combined with EELS to conduct cutting-edge experiments that were not previously possible.
Application: Understanding transistor control with atomic-resolution EELS
It is useful to perform atomic EELS analysis of oxides on II-V semiconductors to extract intensity line profiles from the As, O and Ga. In the example below, you can clearly resolve the dumbbell structure of GaAs (left-hand side of the color map), plus the Ga and As atomic columns are visible. The interface region also shows the presence of Ga2O monolayer responsible for keeping Fermi level unpinned, which allows the electronic device to be turned on or off. Sample courtesy of University of Glasgow. Microscope courtesy of Dr. Yan Xin at Florida State University, Tallahassee, FL. Acknowledgement to Dr. Toshiro Aoki (now at UC-Irvine) for helping set up the microscope for the experiment.
EDS
Gatan supports simultaneous EELS & EDS acquisition with the STEMPack system and GMS 3. EDS spectra and maps can both be collected and analyzed using GMS 3 with workflows similar to the familiar EELS spectroscopy and spectrum imaging workflows. The multimodal workflow within GMS 3 also means that EDS data can be correlated with EELS, 4D STEM, cathodoluminescence, and imaging data captured with GMS 3.
EFTEM
EFTEM is a great method for large-scale chemical imaging of a specimen, as the technique can improve contrast and create a variety of chemical maps. A single set of data can be used to generate various unique contrast features for many different chemical maps.
Gatan Microscopy Suite® (GMS) provides you with a reproducible way to analyze semiconductors with ease. GMS offers a complete re-visioning of electron microscopy's leading software with a simplified user interface and experiment-oriented workflows for imaging, 4D STEM, EELS, EDS, and EFTEM data collection and analysis. This software offers a fully interactive user interface including hardware and microscope control, streamlined data handling with technique-based workflow, and user-friendly EELS and EDS quantification to make sure your results are the focus, not the process to get them.
New features and analysis routines are continuously added to make GMS ever more flexible and powerful for analyzing data across all techniques. The latest versions of GMS 3 include routines for differential phase contrast (DPC) 4D STEM analysis, improvements for MLLS/NLLS, EELS quantification, and more. Moreover, GMS 3 supports Python scripting to bring user-created routines into your analysis workflow inside of GMS. The video playlist below includes detailed tutorials for many of these features.