Abstract Quantitative analysis methods based on the usage of a scanning electron microscope (SEM), such as energy-dispersive X-ray spectroscopy, often require specimens to have a flat surface oriented normal to the electron beam. In-situ procedures for putting microscopic flat surfaces into this orientation generally rely on stereoscopic methods that measure the change in surface vector projections when the surface is tilted by some known angle. Although these methods have been used in the past, there is no detailed statistical analysis of the uncertainties involved in such methods, which leaves an uncertainty in how precisely a specimen can be oriented. Here, we present a first principles derivation of a specimen orientation method and apply our method to a flat sample to demonstrate it. Unlike previous works, we develop a computer vision program using the scale-invariant feature transform to automate and expedite the process of making measurements on our SEM images, thus enabling a detailed statistical analysis of the method with a large sample size. We find that our specimen orientation method is able to orient flat surfaces with high precision and can further provide insight into errors involved in the standard SEM rotation and tilt operations.
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This content will become publicly available on August 25, 2024
Specimen plane orientation determination for analysis based on scanning electron microscope: Comparing top‐down and side‐view approaches
Many attachments to a scanning electron microscope (SEM), such as energy dispersive x‐ray spectroscopy, extend its function significantly. Typically, the application of such attachments requires that the specimen has a planar surface at a specific orientation. It is a challenge to make the plane of a microscale specimen satisfy the orientation requirement since they are visible only in an SEM. An in‐situ procedure is needed to adjust specimen orientation by using stage rotation and tilting functions, in the process of which the key is to determine the initial orientation. This study proposed and tested top‐down and side‐view approaches to determine the orientation of a planar surface inside an SEM. In the top‐down one, the projected area is monitored on SEM images as stage rotation and tilt angles are adjusted. When the surface normal is along the electron beam direction, the area has a maximum value. In the side‐view approach, the stage is adjusted so that the projection appears to be a straight horizontal line on the SEM image. Once the orientation of the specimen for top‐down or side‐view observation is determined, the original can be calculated, and a desired orientation can be realized by manipulating the stage. The procedures have been tested by analyzing planar surfaces of spherical particles in Al‐Cu‐Fe alloy in the form of facets. The measured angles between two surfaces are consistent with those expected from crystallographic consideration within 2.7° and 1.7° for the top‐down and side‐view approaches, respectively.
Top‐down and side‐view approaches have been proposed and tested for in‐situ determination of specimen planar surface orientation in a Scanning Electron Microscope. The measured angles between two surfaces are consistent with those expected from crystallographic consideration within 2.7° and 1.7° for the top‐down and side‐view approaches, respectively.
- NSF-PAR ID:
- 10446976
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Microscopy Research and Technique
- Volume:
- 86
- Issue:
- 12
- ISSN:
- 1059-910X
- Format(s):
- Medium: X Size: p. 1681-1690
- Size(s):
- ["p. 1681-1690"]
- Sponsoring Org:
- National Science Foundation
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