1
|
Zhang T, Britton TB. A simple, static and stage mounted direct electron detector based electron backscatter diffraction system. Micron 2024; 178:103582. [PMID: 38181589 DOI: 10.1016/j.micron.2023.103582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2023] [Revised: 12/19/2023] [Accepted: 12/19/2023] [Indexed: 01/07/2024]
Abstract
To engineer the next generation of advanced materials we must understand their microstructure, and this requires microstructural characterization. This can be achieved through the collection of high contrast, data rich, and insightful microstructural maps. Electron backscatter diffraction (EBSD) has emerged as a popular tool available within the scanning electron microscope (SEM), where maps are realized through the repeat capture and analysis of Kikuchi diffraction patterns. Typical commercial EBSD systems require large and sophisticated detectors that are mounted on the side of the SEM vacuum chamber which can be limiting in terms of widespread access to the technique. In this work, we present an alternative open-hardware solution based upon a compact EBSD system with a simple, static geometry that uses an off-the-shelf direct electron detector co-mounted with a sample. This simple stage is easy to manufacture and improves our knowledge of the diffraction geometry significantly. Microscope and detector control is achieved through software application programming interface (API) integration. After pattern capture, analysis of the diffraction patterns is performed using open-source analysis within AstroEBSD. To demonstrate the potential of this set up, we present two simple EBSD experiments using a line scan and area mapping. We hope that the present system can inspire simpler EBSD system design for widespread access to the EBSD technique and promote the use of open-source software and hardware in the workflow of EBSD experiments.
Collapse
Affiliation(s)
- Tianbi Zhang
- Department of Materials Engineering, The University of British Columbia, 309-6350 Stores Road, Vancouver, BC V6T 1Z4, Canada
| | - T Ben Britton
- Department of Materials Engineering, The University of British Columbia, 309-6350 Stores Road, Vancouver, BC V6T 1Z4, Canada.
| |
Collapse
|
2
|
Marshall AL, Holzer J, Stejskal P, Stephens CJ, Vystavěl T, Whiting MJ. The EBSD spatial resolution of a Timepix-based detector in a tilt-free geometry. Ultramicroscopy 2021; 226:113294. [PMID: 33991964 DOI: 10.1016/j.ultramic.2021.113294] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 03/09/2021] [Accepted: 04/20/2021] [Indexed: 11/26/2022]
Abstract
Performing EBSD with a horizontal sample and a parallel EBSD detector sensor, enables safer specimen movements for data collection of large specimen areas and improves the longitudinal spatial resolution. The collection of electron backscattering patterns (EBSPs) at normal incidence to the electron beam has been revisited via the use of a direct electron detection (DED) sensor. In this article we present a fully operational DED EBSD detection system in this geometry, referred to as the tilt-free geometry. A well-defined Σ=3[101]{121} twin boundary in a Molybdenum bicrystal was used to measure the physical spatial resolution of the EBSD detector in this tilt-free geometry. In this study, two separate methods for estimating the spatial resolution of EBSD, one based on a pattern quality metric and the other on a normalised cross correlation coefficient were used. The spatial resolution was determined at accelerating voltages of 8 kV, 10 kV, 12 kV, 15 kV and 20 kV ranging from ~22-38 nm using the pattern quality method and ~31-46 nm using the normalised cross correlation method.
Collapse
Affiliation(s)
- A L Marshall
- Department of Mechanical Engineering Sciences, The University of Surrey, Guildford, GU2 7XH; Thermo Fisher Scientific, Unit 24 Birches Industrial Estate, East Grinstead, UK, RH19 1UB.
| | - J Holzer
- Institute of Physics of Materials & CEITEC IPM, Academy of Sciences of the Czech Republic, Žižkova 22, 61600 Brno, Czech Republic; Thermo Fisher Scientific, Vlastimila Pecha 1282/12, 62700 Brno, Czech Republic
| | - P Stejskal
- Thermo Fisher Scientific, Vlastimila Pecha 1282/12, 62700 Brno, Czech Republic
| | - C J Stephens
- Thermo Fisher Scientific, Unit 24 Birches Industrial Estate, East Grinstead, UK, RH19 1UB
| | - T Vystavěl
- Thermo Fisher Scientific, Vlastimila Pecha 1282/12, 62700 Brno, Czech Republic
| | - M J Whiting
- Department of Mechanical Engineering Sciences, The University of Surrey, Guildford, GU2 7XH
| |
Collapse
|
3
|
Caplins BW, Holm JD, White RM, Keller RR. Orientation mapping of graphene using 4D STEM-in-SEM. Ultramicroscopy 2020; 219:113137. [PMID: 33096294 PMCID: PMC8022335 DOI: 10.1016/j.ultramic.2020.113137] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 10/08/2020] [Accepted: 10/11/2020] [Indexed: 11/20/2022]
Abstract
A scanning diffraction technique is implemented in the scanning electron microscope. The technique, referred to as 4D STEM-in-SEM (four-dimensional scanning transmission electron microscopy in the scanning electron microscope), collects a diffraction pattern from each point on a sample which is saved to disk for further analysis. The diffraction patterns are collected using an on-axis lens-coupled phosphor/CCD arrangement. Synchronization between the electron beam and the camera exposure is accomplished with off-the-shelf data acquisition hardware. Graphene is used as a model system to test the sensitivity of the instrumentation and develop some basic analysis techniques. The data show interpretable diffraction patterns from monolayer graphene with integration times as short as 0.5 ms with a beam current of 245 pA (7.65×105 incident electrons per pixel). Diffraction patterns are collected at a rate of ca. 100/s from the mm to nm length scales. Using a grain boundary as a 'knife-edge', the spatial resolution of the technique is demonstrated to be ≤5.6nm (edge-width 25 % to 75 %). Analysis of the orientation of the diffraction patterns yields an angular (orientation) precision of ≤0.19∘ (full width at half maximum) for unsupported monolayer graphene. In addition, it is demonstrated that the 4D datasets have the information content necessary to analyze complex and heterogeneous multilayer graphene films.
Collapse
Affiliation(s)
- Benjamin W Caplins
- National Institute of Standards and Technology, Applied Chemicals and Materials Division, Boulder, CO, 80305, United States.
| | - Jason D Holm
- National Institute of Standards and Technology, Applied Chemicals and Materials Division, Boulder, CO, 80305, United States
| | - Ryan M White
- National Institute of Standards and Technology, Applied Chemicals and Materials Division, Boulder, CO, 80305, United States
| | - Robert R Keller
- National Institute of Standards and Technology, Applied Chemicals and Materials Division, Boulder, CO, 80305, United States
| |
Collapse
|
4
|
Wang F, Echlin MP, Taylor AA, Shin J, Bammes B, Levin BDA, De Graef M, Pollock TM, Gianola DS. Electron backscattered diffraction using a new monolithic direct detector: High resolution and fast acquisition. Ultramicroscopy 2020; 220:113160. [PMID: 33197699 DOI: 10.1016/j.ultramic.2020.113160] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2020] [Revised: 10/19/2020] [Accepted: 11/01/2020] [Indexed: 11/19/2022]
Abstract
A monolithic active pixel sensor based direct detector that is optimized for the primary beam energies in scanning electron microscopes is implemented for electron back-scattered diffraction (EBSD) applications. The high detection efficiency of the detector and its large array of pixels allow sensitive and accurate detection of Kikuchi bands arising from primary electron beam excitation energies of 4 keV to 28 keV, with the optimal contrast occurring in the range of 8-16 keV. The diffraction pattern acquisition speed is substantially improved via a sparse sampling mode, resulting from the acquisition of a reduced number of pixels on the detector. Standard inpainting algorithms are implemented to effectively estimate the information in the skipped regions in the acquired diffraction pattern. For EBSD mapping, an acquisition speed as high as 5988 scan points per second is demonstrated, with a tolerable fraction of indexed points and accuracy. The collective capabilities spanning from high angular resolution EBSD patterns to high speed pattern acquisition are achieved on the same detector, facilitating simultaneous detection modalities that enable a multitude of advanced EBSD applications, including lattice strain mapping, structural refinement, low-dose characterization, 3D-EBSD and dynamic in situ EBSD.
Collapse
Affiliation(s)
- Fulin Wang
- Materials Department, University of California Santa Barbara, Santa Barbara, CA 93117, USA
| | - McLean P Echlin
- Materials Department, University of California Santa Barbara, Santa Barbara, CA 93117, USA
| | - Aidan A Taylor
- Materials Department, University of California Santa Barbara, Santa Barbara, CA 93117, USA
| | - Jungho Shin
- Materials Department, University of California Santa Barbara, Santa Barbara, CA 93117, USA
| | | | | | - Marc De Graef
- Department of Materials Science and Engineering, Carnegie Mellon University, Pittsburgh, PA 15213, USA
| | - Tresa M Pollock
- Materials Department, University of California Santa Barbara, Santa Barbara, CA 93117, USA
| | - Daniel S Gianola
- Materials Department, University of California Santa Barbara, Santa Barbara, CA 93117, USA.
| |
Collapse
|
5
|
On the resolution of EBSD across atomic density and accelerating voltage with a particular focus on the light metal magnesium. Ultramicroscopy 2019; 207:112828. [DOI: 10.1016/j.ultramic.2019.112828] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Revised: 08/09/2019] [Accepted: 08/21/2019] [Indexed: 11/22/2022]
|