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Electron Channeling Contrast Imaging for Rapid III-V Heteroepitaxial Characterization
Published on: July 17, 2015
Imaging the phase separation in atomically thin buried SrTiO(3) layers by electron channeling
L Fitting Kourkoutis1, C Stephen Hellberg, V Vaithyanathan
1School of Applied and Engineering Physics, Cornell University, Ithaca, NY 14853, USA.
Physical Review Letters
|February 1, 2008
Summary
Thin strontium titanate (SrTiO3) films on silicon (Si) exhibit phase separation. This dewetting instability leads to island formation, as revealed by advanced electron microscopy and supported by theoretical calculations.
Area of Science:
- Materials Science
- Surface Science
- Thin Film Physics
Background:
- Strontium titanate (SrTiO3) thin films are crucial for electronic applications.
- Understanding film growth instabilities on silicon substrates is essential for device fabrication.
Purpose of the Study:
- To investigate the dewetting and phase separation instability in thin SrTiO3 films grown on Si(100).
- To characterize the film morphology and atomic structure at the nanoscale.
Main Methods:
- Scanning transmission electron microscopy (STEM) was employed for high-resolution imaging.
- Electron channeling was utilized to achieve sub-nanometer beam focusing.
- Density-functional theory (DFT) calculations were performed to predict the material's ground state.
Main Results:
- Phase-separation instability leading to dewetting of SrTiO3 films was observed.
- Nonuniform coverage with epitaxial SrTiO3 islands and Sr-covered regions was revealed.
- DFT predicted a ground state of coexisting reconstructed Si and Sr-deficient SrTiO3, matching experimental findings.
Conclusions:
- The study demonstrates a phase-separation instability in SrTiO3 films on Si(100).
- Advanced imaging techniques coupled with theoretical calculations provide insights into film morphology and growth mechanisms.
