Comparative study of GeO2/Ge and SiO2/Si structures on anomalous charging of oxide films upon water adsorption revealed by ambient-pressure X-ray photoelectron spectroscopy

• Mori, Daichi

• Oka, Hiroshi

• Hosoi, Takuji

• Kawai, Kentaro

• Morita, Mizuho

• Crumlin, Ethan J.

• Liu, Zhi

• Watanabe, Heiji

• Arima, Kenta

抄録

Mori D., Oka H., Hosoi T., et al. Comparative study of GeO2/Ge and SiO2/Si structures on anomalous charging of oxide films upon water adsorption revealed by ambient-pressure X-ray photoelectron spectroscopy. Journal of Applied Physics, 120, 9, 095306. https://doi.org/10.1063/1.4962202.

The energy difference between the oxide and bulk peaks in X-ray photoelectron spectroscopy (XPS) spectra was investigated for both GeO2/Ge and SiO2/Si structures with thickness-controlled water films. This was achieved by obtaining XPS spectra at various values of relative humidity (RH) of up to ∼15%. The increase in the energy shift is more significant for thermal GeO2 on Ge than for thermal SiO2 on Si above ∼10-4% RH, which is due to the larger amount of water molecules that infiltrate into the GeO2 film to form hydroxyls. Analyzing the origins of this energy shift, we propose that the positive charging of a partially hydroxylated GeO2 film, which is unrelated to X-ray irradiation, causes the larger energy shift for GeO2/Ge than for SiO2/Si. A possible microscopic mechanism of this intrinsic positive charging is the emission of electrons from adsorbed water species in the suboxide layer of the GeO2 film to the Ge bulk, leaving immobile cations or positively charged states in the oxide. This may be related to the reported negative shift of flat band voltages in metal-oxide-semiconductor diodes with an air-exposed GeO2 layer.

収録刊行物

• Journal of Applied Physics

  Journal of Applied Physics 120 (9), 095306-1-095306-10, 2016-09-02

  American Institute of Physics

キーワード

• General Physics and Astronomy

詳細情報

• CRID: 1050581168900634624
• NII論文ID: 120007145772
• NII書誌ID: AA11868165
• DOI: 10.1063/1.4962202
• ISSN: 10897550
• ISSN: 00218979
• HANDLE: 11094/83923
• Web Site: https://pubs.aip.org/aip/jap/article-pdf/doi/10.1063/1.4962202/13428766/095306_1_online.pdf
• 本文言語コード: en
• 資料種別: journal article
• データソース種別:
  • IRDB
  • Crossref
  • CiNii Articles
  • KAKEN