AstroECP: towards more practical Electron Channeling Contrast Imaging

TL;DR

This paper presents AstroECP, an open-source software and systematic workflow that enhances the practicality and quantitative analysis capabilities of Electron Channeling Contrast Imaging (ECCI) in SEM, enabling better defect characterization.

Contribution

Introduction of AstroECP, a new open-source tool and workflow that optimizes ECCI signal contrast and calibration for more accurate defect imaging in SEM.

Findings

Successful application to threading dislocations in GaAs

Validation of ECCI contrast with precession-based methods

Guidelines for high-resolution defect imaging

Abstract

Electron channeling contrast imaging (ECCI) is a scanning electron microscopy (SEM) based technique that enables bulk-sample characterization of crystallographic defects (e.g. dislocations, stacking faults, low angle boundaries). Despite its potential, ECCI remains underused for quantitative defect analysis as compared to transmission electron microscope (TEM) based methods. Here, we overcome barriers that limit the use of ECCI including optimizing signal-to-noise contrast, precise determination of the incident beam vector with calibrated and easy to use simulations and experimental selected area electron channeling patterns (SA-ECP). We introduce a systematic ECCI workflow, alongside a new open-source software tool (AstroECP), that includes calibration of stage tilting, SA-ECP field of view, and the energy that forms the ECP/ECCI contrast using dynamical simulations. The functionality of this workflow is demonstrated with case studies that include threading dislocations in GaAs and the cross validation of precession based ECCI-contrast, which is otherwise known as Electron Channeling Orientation Determination (eCHORD). To assist the reader, we also provide best practice guidelines for ECCI implementation to promote high-resolution defect imaging in the SEM.