ALIGNMENT OF FEATURELESS THIN FILM IN TEM

摘要

PROBLEM TO BE SOLVED: To provide a method for placing a featureless thin film on a diffraction plane to form a self-centering hole-free phase plate in a transmission electron microscope.SOLUTION: A transmission electron microscope includes: an electron source 104; a condenser system 106 for forming parallel electron beams on a sample surface; an objective lens 112 for focusing the parallel electron beams on a diffraction plane 114; a featureless thin film positioned in or close to the diffraction plane or a plane conjugated to the diffraction plane; and a detector 124 for recording images formed on an image plane. A method for aligning a thin film in the transmission electron microscope includes the steps of: focusing the condenser system 106 with a first excitation associated with a first position of the diffraction plane; illuminating the thin film with the focused electron beam; and determining from a recorded image whether or not the illumination is an on-plane illumination when the thin film is located in the diffraction plane or a plane conjugated thereto, and changing the excitation of the condenser system 106 to change the position of the diffraction plane or changing the position of the thin film along an optical axis 102, repeatedly until the illumination is an in-plane illumination.SELECTED DRAWING: Figure 1