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Title: Detecting Fermi-level shifts by Auger electron spectroscopy in Si and GaAs

Abstract

In this paper, changes in surface Fermi-level of Si and GaAs, caused by doping and cleaning, are investigated by Auger electron spectroscopy. Based on the Auger voltage contrast, we compared the Auger transition peak energy but with higher accuracy by using a more accurate detector and an improved peak position determination method. For silicon, a peak shift as large as 0.46 eV was detected when comparing a cleaned p-type and n-type wafer, which corresponds rather well with the theoretical difference in Fermi-level. If no cleaning was applied, the peak position did not differ significantly for both wafer types, indicating Fermi-level pinning in the band gap. For GaAs, peak shifts were detected after cleaning with HF and (NH4)2S-solutions in an inert atmosphere (N2-gas). Although the (NH4)2S-cleaning in N2 is very efficient in removing the oxygen from the surface, the observed Ga- and As-peak shifts are smaller than those obtained after the HF-cleaning. It is shown that the magnitude of the shift is related to the surface composition. After Si-deposition on the (NH4)2S-cleaned surface, the Fermi-level shifts back to a similar position as observed for an as-received wafer, indicating that this combination is not successful in unpinning the Fermi-level of GaAs. Thismore » work has been funded by J.D.'s PhD fellowship of the Fund of Scientific Research-Flanders (FWO-V) (Dossier No. 11U4516N). P.H. acknowledges support from Becas Chile-CONICYT. This research was also supported by the FWO Odysseus Program, the Belgian Hercules Stichting with the Project No. Her/08/25 and AKUL/13/19 and the KU Leuven project GOA "Fundamental challenges in Semiconductor Research". The authors would also like to thank Bastiaan Opperdoes and Ludwig Henderix for technical support. The work was supported by the U.S. Department of Energy (USDOE), Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, and performed in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). Battelle operates PNNL for the USDOE under contract DE-AC05-76RL01830.« less

Authors:
; ; ; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
1455263
Report Number(s):
PNNL-SA-130366
Journal ID: ISSN 0169-4332; 49306; KC0203020
DOE Contract Number:
AC05-76RL01830
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Surface Science; Journal Volume: 440; Journal Issue: C
Country of Publication:
United States
Language:
English
Subject:
Environmental Molecular Sciences Laboratory

Citation Formats

Debehets, J., Homm, P., Menghini, M., Chambers, S. A., Marchiori, C., Heyns, M., Locquet, J. P., and Seo, J. W. Detecting Fermi-level shifts by Auger electron spectroscopy in Si and GaAs. United States: N. p., 2018. Web. doi:10.1016/j.apsusc.2018.01.079.
Debehets, J., Homm, P., Menghini, M., Chambers, S. A., Marchiori, C., Heyns, M., Locquet, J. P., & Seo, J. W. Detecting Fermi-level shifts by Auger electron spectroscopy in Si and GaAs. United States. doi:10.1016/j.apsusc.2018.01.079.
Debehets, J., Homm, P., Menghini, M., Chambers, S. A., Marchiori, C., Heyns, M., Locquet, J. P., and Seo, J. W. Tue . "Detecting Fermi-level shifts by Auger electron spectroscopy in Si and GaAs". United States. doi:10.1016/j.apsusc.2018.01.079.
@article{osti_1455263,
title = {Detecting Fermi-level shifts by Auger electron spectroscopy in Si and GaAs},
author = {Debehets, J. and Homm, P. and Menghini, M. and Chambers, S. A. and Marchiori, C. and Heyns, M. and Locquet, J. P. and Seo, J. W.},
abstractNote = {In this paper, changes in surface Fermi-level of Si and GaAs, caused by doping and cleaning, are investigated by Auger electron spectroscopy. Based on the Auger voltage contrast, we compared the Auger transition peak energy but with higher accuracy by using a more accurate detector and an improved peak position determination method. For silicon, a peak shift as large as 0.46 eV was detected when comparing a cleaned p-type and n-type wafer, which corresponds rather well with the theoretical difference in Fermi-level. If no cleaning was applied, the peak position did not differ significantly for both wafer types, indicating Fermi-level pinning in the band gap. For GaAs, peak shifts were detected after cleaning with HF and (NH4)2S-solutions in an inert atmosphere (N2-gas). Although the (NH4)2S-cleaning in N2 is very efficient in removing the oxygen from the surface, the observed Ga- and As-peak shifts are smaller than those obtained after the HF-cleaning. It is shown that the magnitude of the shift is related to the surface composition. After Si-deposition on the (NH4)2S-cleaned surface, the Fermi-level shifts back to a similar position as observed for an as-received wafer, indicating that this combination is not successful in unpinning the Fermi-level of GaAs. This work has been funded by J.D.'s PhD fellowship of the Fund of Scientific Research-Flanders (FWO-V) (Dossier No. 11U4516N). P.H. acknowledges support from Becas Chile-CONICYT. This research was also supported by the FWO Odysseus Program, the Belgian Hercules Stichting with the Project No. Her/08/25 and AKUL/13/19 and the KU Leuven project GOA "Fundamental challenges in Semiconductor Research". The authors would also like to thank Bastiaan Opperdoes and Ludwig Henderix for technical support. The work was supported by the U.S. Department of Energy (USDOE), Office of Science, Office of Basic Energy Sciences, Division of Materials Sciences and Engineering, and performed in the Environmental Molecular Sciences Laboratory, a national scientific user facility sponsored by the Department of Energy's Office of Biological and Environmental Research and located at Pacific Northwest National Laboratory (PNNL). Battelle operates PNNL for the USDOE under contract DE-AC05-76RL01830.},
doi = {10.1016/j.apsusc.2018.01.079},
journal = {Applied Surface Science},
number = C,
volume = 440,
place = {United States},
year = {Tue May 01 00:00:00 EDT 2018},
month = {Tue May 01 00:00:00 EDT 2018}
}