Journal of Electron Microscopy Advance Access originally published online on March 1, 2006
Journal of Electron Microscopy 2006 55(1):1-5; doi:10.1093/jmicro/dfi073
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High-resolution transmission electron microscopy and electron energy-loss spectroscopy study of polycrystalline-Si/ZrO2/SiO2/Si metal-oxide-semiconductor structures
1 National Nanofab Center 53-3, Eoeun-dong, Yuseong-gu, Daejeon 305-806, Korea
2 Institute of Multidisciplinary Research for Advanced Materials, Tohoku University Sendai 980-8577, Japan
3 Department of Electronic Engineering, Yeojoo Institute of Technology Yeojoo 469-705, Korea
4 JEOL Ltd Akishima, Tokyo 196-8558, Japan
*To whom correspondence should be addressed. E-mail: jmyang{at}nnfc.com
Crystallographic and interfacial characteristics of polycrystalline-Si/ZrO2/SiO2/Si metal-oxide-semiconductor (MOS) structures were investigated at the atomic scale by high-resolution transmission electron microscopy (HRTEM) and electron energy-loss spectroscopy (EELS) combined with the annular dark-field scanning transmission electron microscopy. The HRTEM and electron diffraction results showed that the ZrO2 film exhibited a mixed structure of the tetragonal (P
m2) and the monoclinic (P21/c) phases. Moreover, ZrSi nodules formed by the reaction of Zr with polycrystalline-Si were evaluated to be ZrSi2 of the orthorhombic phase or Zr5Si4 of the tetragonal phase. From the EELS results, Zr atoms were detected at the upper and bottom interfaces of the SiO2 film, and the interfacial SiO2 layer with thickness <1 nm was observed at the polycrystalline-Si/ZrO2 interface. The interfacial reactions directly influence the electrical properties of the MOS structures.
Keywords Si semiconductor, ZrO2, high-resolution transmission electron microscopy, electron energy-loss spectroscopy, annular-dark field scanning transmission electron microscopy
Received 22 September 2005, accepted 18 January 2006