STEM Diffraction Imaging with Simultaneous Dark Field Detection
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Solution Overview
Problem
Current analysis methods using nano beam electron diffraction (NBD) with scanning transmission electron microscopes often cause sample damage due to electron beam radiation and struggle with acquiring high-accuracy electron diffraction images.
Innovation Solution
The method employs an annular first detector for dark field imaging and a second detector for electron diffraction, scanning multiple radiation points on the sample at preset incidence angles to detect dark field and electron diffraction images simultaneously, reducing sample damage and improving image accuracy by integrating NBD images with corrected radiation positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electron beam radiation is used for NBD analysis, then crystal orientation can be specified in local area, but sample damage occurs due to electron beam radiation
Solution Approach 1:
The analysis area is divided into multiple radiation points that are scanned sequentially. By distributing the electron beam radiation across multiple points rather than concentrating it on one location, the cumulative damage to any single point is reduced while still obtaining comprehensive diffraction data from the entire analysis area.
Solution Approach 2:
The electron beam is scanned periodically across multiple radiation points in a systematic sequence. This periodic scanning allows the sample to recover between irradiation events at each point, reducing cumulative damage while maintaining measurement precision through repeated measurements at different locations.
2Measurement precision
If multiple radiation points are scanned sequentially, then comprehensive diffraction data can be obtained, but analysis time increases
Solution Approach 1:
Dark field image detection and electron diffraction image detection are merged into a single simultaneous detection process. By using two detectors that operate concurrently during the scanning process, the patent obtains both types of data in one pass rather than requiring separate scanning operations, thereby reducing total analysis time while maintaining comprehensive data quality.
Solution Approach 2:
The scanning process continuously collects both dark field and diffraction data at each radiation point without interruption. The simultaneous detection ensures that data collection is continuous and efficient, eliminating idle time between different measurement modes and maximizing the information gained per unit time.
3Measurement precision
If dark field imaging and electron diffraction detection are performed separately, then each measurement can be optimized, but total measurement time and sample exposure increase
Solution Approach 1:
The patent merges dark field imaging and electron diffraction detection into a single integrated measurement process. Two detectors simultaneously capture different types of information from the same electron beam interaction events, eliminating the need for separate scanning operations and reducing total measurement time while maintaining optimized detection for each modality.
Solution Approach 2:
The detection system is designed with multi-functionality, where two detectors simultaneously perform different measurement functions (dark field imaging and electron diffraction) during the same scanning process. This universal approach allows the system to optimize both measurement types without requiring separate dedicated scanning operations.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach allows for the acquisition of high-accuracy electron diffraction images while minimizing sample damage from electron beam radiation, enhancing the precision of crystal orientation analysis.
Implementation Method 1
accelerating electron beams emitted from a beam radiation unit, irradiating the sample so that focal points of the electron beams are located on the sample
Implementation Method 2
detecting electron beams that are transmitted through the sample or scattered from the sample... detecting electron diffraction images of the sample
Implementation Method 3
an annular first detector that detects dark field images in a sample by accelerating electron beams... and detecting electron beams that are transmitted through the sample or scattered from the sample
Data Source
AI summary
According to one embodiment, there is provided an analysis method by a scanning transmission electron microscope including a dark field detector that detects dark field images by irradiating a sample with electron beams and detecting electron beams that are transmitted through or scattered from the sample, and an electron beam detector that detects electron diffraction images at radiation points of the electron beams among the electron beams that are transmitted through the sample or scattered from detecting the electron beams transmitted through a hollow portion of the dark field detector. The analysis method includes scanning a plurality of the radiation points set in an attention area by sequentially radiating electron beams at preset incidence angles, and performing detection of dark field images of the attention area and detection of NBD images at each of the plurality of radiation points at the same time.