Study of Sn and Mg doping effects on TiO2/Ge stack structure by combinatorial synthesis

Takahiro Nagata, Yoshihisa Suzuki, Yoshiyuki Yamashita, Atsushi Ogura, Toyohiro Chikyow

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1 Citation (Scopus)


The effects of Sn and Mg doping of a TiO2 film on a Ge substrate were investigated to improve leakage current properties and Ge diffusion into the TiO2 film. For systematic analysis, dopant-composition-spread TiO2 samples with dopant concentrations of up to 20.0 at.% were fabricated by RF sputtering and a combinatorial method. X-ray photoelectron spectroscopy revealed that the instability of Mg doping of TiO2 at dopant concentrations above 10.5 at.%. Both Sn and Mg dopants reduced Ge diffusion into TiO2. Sn doping enhanced the crystallization of the rutile phase, which is a high-dielectric-constant phase, although the Mg-doped TiO2 film indicated an amorphous structure. Sn-doping indicated systematic leakage current reduction with increasing dopant concentration. Doping at Sn concentrations higher than 16.8 at.% improved the leakage properties (∼10-7 A/cm2 at -3.0V) and capacitance-voltage properties of metal-insulator-semiconductor (MIS) operation. The Sn doping of TiO2 may be useful for interface control and as a dielectric material for Ge-based MIS capacitors.

Original languageEnglish
Article number04FJ04
JournalJapanese journal of applied physics
Issue number4
Publication statusPublished - 2018 Apr
Externally publishedYes

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)


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