Imaging a sample in a TEM equipped with a phase plate
AssigneesFEI Company, Max-Planck-Gesellschaft zur Foerderung der Wissenschaften e.V.
InventorsBart Buijsse, Marco Hugo Petrus Moers, Radostin Stoyanov Danev
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Abstract
The invention relates to a method of forming an image of a sample in a transmission electron microscope equipped with a phase plate. Prior art use of such a phase plate can introduce artifacts in the form of ringing and a halo. These artifacts are caused by the abrupt changes in the Fourier domain due to the sharp edges of the phase plate in the diffraction plane. By moving the phase plate with respect to the non-diffraction beam (the diffraction pattern) while recording an image the sudden transition in the Fourier domain is changed to a more gradual transition, resulting in less artifacts.
Claims20
A method of forming an image of a sample in a transmission electron microscope, the sample irradiated by a beam of electrons and the sample splitting the beam of electrons in a beam of undiffracted electrons and beams of scattered electrons, the electron microscope equipped with a contrast enhancing device from the group of phase plates, Foucault devices or Hilbert devices, the contrast enhancing device for improving the contrast at low spatial frequencies, the contrast enhancing device positioned in the back focal plane of the objective lens or in an image of said plane, the contrast enhancing device having a position with respect to the beam of unscattered electrons,
- wherein:
- during the formation of the image the mutual position of the contrast enhancing device and the beam of unscattered electrons is changed.
A Transmission Electron Microscope for acquiring an image of a sample, the microscope equipped with a phase enhancing device and a programmable controller for controlling the microscope, wherein the controller is programmed to control the microscope in such a manner that the beam is moved over the phase enhancing device while acquiring an image.
A method of forming an image of a sample in a transmission electron microscope, the electron microscope comprising a contrast enhancing device positioned in the back focal plane of the objective lens or in an image of said plane, the method comprising:
- irradiating the sample with a beam of electrons;
- splitting the beam of electrons into a beam of undiffracted electrons and beams of scattered electrons;
- and
- changing the mutual position of the contrast enhancing device and the beam of unscattered electons during the formation of the image.
Dependencies are inferred from the claim text.