Sub-Angstrom transmission electron microscopy at 300keV

Conference · Wed Feb 14 04:00:00 EST 2001

OSTI ID:789145

O'Keefe, Michael A ^[1]; Nelson, E Christian; Turner, John H; Thust, Andreas

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1. LBNL Library

We have demonstrated sub-Angstrom TEM to a resolution of 0.78 Angstrom with the one-Angstrom microscope (OAM) project at the National Center for Electron Microscopy. The OAM combines a modified CM300FEG-UT with computer software able to generate sub-Angstrom images from experimental image series. We achieved sub-Angstrom resolution with the OAM by paying close attention to detail. We placed the TEM in a favorable environment. We reduced its three-fold astigmatism A2 from 2.46mm to 300 Angstrom (corresponding to transfer of 0.68 Angstrom spacings at a pi/4 phase limit). We improved its information limit by minimizing high-voltage and lens current ripple. Energy spread of 0.93eV FWHH gave a focus spread of 20 Angstrom and an information limit of 0.78 Angstrom, allowing successful resolution of the 0.89 Angstrom (400) atom spacings in [110] diamond. As a further test, we reduced the electron gun extraction voltage to 3kV to improve our information limit to 0.75 Angstrom, and then imaged 0 .7 Angstrom (444) atom spacings in [112] silicon as distinct pairs of 'white atoms' near an alpha-null defocus of -3783 Angstrom.

• Research Organization: Ernest Orlando Lawrence Berkeley National Laboratory, Berkeley, CA (US)
• Sponsoring Organization: USDOE Director, Office of Science. Office of Basic Energy Studies. Division of Materials Sciences (US)
• DOE Contract Number: AC03-76SF00098
• OSTI ID: 789145
• Report Number(s): LBNL--47531
• Country of Publication: United States
• Language: English

Related Subjects

47 OTHER INSTRUMENTATION
ATOMS
ELECTRON GUNS
HIGH-RESOLUTION ELECTRON MICROSCOPY SUB-ANGSTROM MICROSCOPY
MICROANALYSIS
SILICON
SPATIAL RESOLUTION
TRANSMISSION ELECTRON MICROSCOPY