Chemical states and electronic structure of a HfO2∕Ge(001) interface

We report the chemical bonding structure and valence band alignment at the HfO2∕Ge(001) interface by systematically probing various core level spectra as well as valence band spectra using soft x rays at the Stanford Synchrotron Radiation Laboratory. We investigated the chemical bonding changes as a...

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Bibliographic Details
Published in:Applied physics letters 2005-07, Vol.87 (4)
Main Authors: Seo, Kang-Ill, McIntyre, Paul C., Sun, Shiyu, Lee, Dong-Ick, Pianetta, Piero, Saraswat, Krishna C.
Format: Article
Language:English
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Summary:We report the chemical bonding structure and valence band alignment at the HfO2∕Ge(001) interface by systematically probing various core level spectra as well as valence band spectra using soft x rays at the Stanford Synchrotron Radiation Laboratory. We investigated the chemical bonding changes as a function of depth through the dielectric stack by taking a series of synchrotron photoemission spectra as we etched through the HfO2 film using a dilute hydrogen fluoride solution. We found that a very nonstoichiometric GeOx layer exists at the HfO2∕Ge interface. The valence band spectra near the Fermi level in each different film structure were carefully analyzed, and as a result, the valence band offset between Ge and GeOx was determined to be ΔEv (Ge–GeOx)=2.2±0.15eV, and that between Ge and HfO2, ΔEv (Ge–HfO2)=2.7±0.15eV.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.2006211