Electron Diffraction Mapping With Multi-Energy Beams for Thick Samples
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Solution Overview
Problem
Conventional methods for determining crystallographic properties of samples, especially those with inhomogeneous thickness, face challenges in obtaining accurate results due to insufficient contrast and superposition of diffraction patterns, leading to blurred or poorly scattered electron diffraction patterns.
Innovation Solution
The method involves generating multiple electron beams with different mean kinetic energies to detect two-dimensional spatial distributions of electrons at various locations within a sample region, allowing for the determination of crystallographic properties by combining data sets from these locations, which can include selecting or combining data based on quality parameters such as contrast and distance proximity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single electron beam with fixed kinetic energy is used to detect diffraction patterns, then the measurement process is simple and fast, but the crystallographic properties cannot be accurately determined for samples with inhomogeneous thickness due to blurred patterns and insufficient contrast
Solution Approach 1:
The patent applies parameter changes by varying the kinetic energy of the electron beam across multiple measurements. Instead of using a single fixed energy, the system performs diffraction pattern acquisition at different electron energies, allowing optimization for different sample thicknesses and improving overall measurement accuracy for inhomogeneous samples.
Solution Approach 2:
The system implements periodic action by systematically cycling through multiple electron beam energies in a structured sequence. Each energy level provides complementary information, and the periodic variation in beam energy enables comprehensive characterization of the sample's crystallographic properties despite thickness variations.
2Measurement precision
If the electron beam kinetic energy is optimized for a specific sample thickness, then diffraction patterns of good quality are obtained for that thickness, but patterns from regions with different thickness become blurred and suffer from too little scattering power or too large absorption
Solution Approach 1:
The patent implements universality by creating a multi-functional measurement system that can handle samples of various thicknesses. By acquiring diffraction patterns at multiple electron energies, the system becomes universally applicable to both thin and thick regions of inhomogeneous samples, with each energy level contributing to the overall characterization.
Solution Approach 2:
The system changes the electron beam energy parameter to adapt to different sample thicknesses. This parameter variation allows the same measurement system to optimize diffraction pattern quality across regions with varying thickness, overcoming the limitation of single-energy systems that can only be optimized for one specific thickness.
3Measurement precision
If multiple electron beams with different kinetic energies are used to detect diffraction patterns, then accurate crystallographic properties can be determined for inhomogeneous samples, but the measurement time and data processing complexity increase
Solution Approach 1:
The system performs preliminary actions by acquiring diffraction patterns at multiple electron energies before final analysis. This preliminary multi-energy data collection enables subsequent processing to select or combine the most informative patterns, improving accuracy while managing measurement time through structured acquisition.
Solution Approach 2:
The measurement system incorporates feedback by evaluating the quality of diffraction patterns at different energies and using this information to guide further measurements or data selection. This feedback mechanism optimizes the balance between measurement time and accuracy by focusing resources on the most informative energy levels.
4Quantity of substance
If the sample is not sufficiently thin, then more material can be analyzed, but the diffraction pattern shows insufficient contrast and may comprise superposition of plural individual diffraction patterns from multiple sections
Solution Approach 1:
The patent applies parameter changes by varying electron beam energy to optimize penetration depth and scattering cross-section. At higher energies, electrons can penetrate thicker samples while maintaining adequate contrast, and the energy variation allows differentiation between signals from different depth sections through characteristic energy-dependent scattering patterns.
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 enables accurate determination of crystallographic properties, including lattice orientation and type, by improving the quality of diffraction patterns and accounting for variations in sample thickness, resulting in enhanced precision and clarity of image representations.
Implementation Method 1
analyzing electron diffraction patterns of the sample wherein the electron diffraction patterns comprise Kikuchi bands
Implementation Method 2
detecting an electron diffraction pattern for each of the locations
Implementation Method 3
the electron diffraction patterns comprise Kikuchi bands
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Method of determining crystallographic properties of a sample comprises: generating first and second electron beams of electrons having first and second mean kinetic energies, respectively; detecting, for each of first locations of a region of the sample, a two-dimensional spatial distribution of electrons incident onto a detection area while directing the first electron beam onto the first locations; generating, for each of the first locations, first data representing the two-dimensional spatial distribution; detecting, for each of second locations of the region of the sample, a two-dimensional spatial distribution of electrons incident onto the detection area while directing the second electron beam onto the second locations; generating, for each of the second locations, second data representing the two-dimensional spatial distribution; and determining the crystallographic properties for target locations of the region based on the first data of the first locations and the second data of the second locations.