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Sub-nanoscale electron microscopy of complex nanostructures

Summary

The aim of this project is to develop robust, quantitative measurement methods utilizing transmission electron microscopy methods for complex, nanostructured devices with nanometer and sub-nanometer spatial resolution.

Description

subnanoscale electron microscopy figure

Dark-field scanning transmission electron microscopy (STEM) image (top) of an Er doped CaF2 nanoparticle.  In this image mode, the dopant atom locations are indicated by the brigher atomic columns and can be readily identified. (Sample provided by Taejong Paik (University of Pennsylvania)). Dark-field STEM image (bottom left) of tri-gate transistor specimen.  Color arrows indicate the location where reconstructions of the 3D structure were extracted (bottom right).  Also shown is a volumetric rendering of the full 3D volume (bottom left, inset)

The properties of advance materials are becoming ever more reliant on the ability to manipulate their structure at very fine length scales. For example, the relevant feature sizes in state of the art transistors continues to decrease, even as the complexity of the architectures employed increases, and existing characterization methods are proving insufficient for analyzing such devices. Transmission electron microscopy (TEM) with its unique atomic resolution and analytical capabilities has become a crucial and irreplaceable tool in many industries for the characterization of materials. The focus of this program is the development and application of electron microscopy methods for high spatial resolution characterization with an emphasis on improving reproducibility and quantification.

Major Accomplishments

Artifact free reconstruction of real transistor architectures.

Automated alignment and reconstruction methods for quantitative 3D structural and chemical characterization in electron tomography of cylindrical specimens.

Integration of spectroscopic and image signal acquisition for improved contrast between different materials and phases.

Identified an imaging mode capable of qualitative in-situ tracking of oxidation state in CeO2 nanomaterials.

Elucidated the role of certain measurement parameters in quantitative oxidation measurements of CeO2 nanomaterials.

Created August 2, 2017, Updated August 4, 2017