Fabrication of Ge MOS with low interface trap density by ALD of Al2O3 on epitaxially grown Ge

Ryotaro Matsuoka, Eriko Shigesawa, Satoru Miyamoto, Kentarou Sawano, Kohei M. Itoh

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)


Effects of initial surface conditions on interface characteristics of Al2O3/GeOx/Ge gate stacks are studied. As a clean surface condition prior to atomic layer deposition (ALD), a non-terminated Ge surface is realized by the insertion of an epitaxial Ge layer are grown on a Ge substrates in a MBE chamber which is directly connected to an ALD chamber. For these structures, the fixed charge density (Q f) and interface trap density (D it) are evaluated from the C-V characteristics and conductance method. Q f reduction of about 17% and 90% are achieved by insertion of the epi-Ge layer and additional GeOx formation using plasma post-oxidation, respectively. A 90% reduction of D it is also confirmed. These results indicate the importance of the initial Ge surface conditions before ALD and the Al2O3/GeOx/Ge gate stacks are very promising for high mobility Ge based CMOS applications.

Original languageEnglish
Article number014004
JournalSemiconductor Science and Technology
Issue number1
Publication statusPublished - 2019 Jan


  • AlO
  • CV
  • Ge
  • epitaxy
  • interface
  • trap

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering
  • Materials Chemistry


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