Reciprocal Space Map Generation via Beam Tilt

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Solution Overview

Problem

Existing methods for generating reciprocal space maps of crystalline materials are limited by the need for careful deformation of thin specimens for bend contours and the small volume probing of highly focused charged particle beams, which restricts the accessibility and accuracy of crystallographic information.

Innovation Solution

A method involving irradiation of a sample with a charged particle beam at multiple incident angles by tilting the beam relative to the sample around two perpendicular axes, allowing for the formation of reciprocal space maps without deforming the sample, enabling the extraction of crystallographic information from line features in the maps.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a highly focused charged particle beam is used to probe the sample, then the measurement precision of crystallographic information is improved, but the volume of sample probed is limited to a small region

Engineering Contradiction:

Improvecrystallographic information precisionVSAvoidsample volume probed

Core Design Contradiction:

Measurement precisionVSVolume of moving object

Solution Approach 1:

The method segments the reciprocal space mapping process by using a focused charged particle beam to probe different regions of the sample at multiple incident angles. Each measurement probes a small volume with high precision, and the data from multiple measurements are combined to reconstruct the complete reciprocal space map, thus achieving both high precision and comprehensive coverage.

Inventive Principle:

Principle #1Segmentation

2Measurement precision

If bend contours are formed by deforming the sample, then the reciprocal space mapping capability is improved, but the ease of operation deteriorates due to requiring careful deformation of thin specimens

Engineering Contradiction:

Improvereciprocal space mapping capabilityVSAvoidsample preparation complexity

Core Design Contradiction:

Measurement precisionVSEase of operation

Solution Approach 1:

Instead of deforming the sample to achieve reciprocal space mapping (as in traditional bend contour methods), this invention inverts the approach by keeping the sample flat and instead varying the incident angle of the charged particle beam. This is achieved by tilting the beam around two perpendicular axes, eliminating the need for sample deformation while maintaining the ability to map reciprocal space.

Inventive Principle:

Principle #13The other way round (Inversion)

3Loss of information

If multiple incident angles are used to generate reciprocal space map, then the comprehensiveness of crystallographic information is improved, but the measurement time increases

Engineering Contradiction:

Improvecrystallographic information completenessVSAvoidmeasurement time

Core Design Contradiction:

Loss of informationVSLoss of time

Solution Approach 1:

The method adds angular dimensions to the measurement process by tilting the charged particle beam around two perpendicular axes. This allows sampling of reciprocal space along multiple directions, providing comprehensive crystallographic information. The systematic variation of incident angles in two dimensions enables complete reciprocal space mapping while optimizing measurement efficiency.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 the generation of reciprocal space maps for any location within the field of view without sample deformation, providing comprehensive crystallographic information and extending the range of tilt angles, thus improving the accuracy and accessibility of structural analysis.

Implementation Method 1

both Bragg diffraction form discrete atomic positions and Kikuchi lines formed from thermally-induced diffuse scattering combine to form the primary features in the convergent-beam electron diffraction (CBED) patterns

Methodology Applied

Scientific EffectBragg diffraction: Bragg Diffraction

Implementation Method 2

Kikuchi lines formed from thermally-induced diffuse scattering

Methodology Applied

Scientific EffectKikuchi lines formation: Diffusion

Data Source

PatentUS11430632B2Method and system for generating reciprocal space map

Publication Date: 2022.08.30 FEI CO

AI summary

Reciprocal space map of specific sample locations is generated based on the sample images acquired by irradiating the sample with a charged particle beam at multiple incident angles. The incident angles are obtained by tilting the charged particle beam and/or the sample around two perpendicular axes within the sample plane. The reciprocal space map of a selected sample location is generated based on intensity of pixels corresponding to the location in the sample images.