High electron mobility germanium FinFET fabricated by atomic layer defect-free and roughness-free etching

Daisuke Ohori, Takuya Fujii, Shuichi Noda, Wataru Mizubayashi, Kazuhiko Endo, Yao Jen Lee, Jenn Hwan Tarng, Yiming Li, Seiji Samukawa

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


We investigated a high electron mobility Ge FinFET fabricated by defect-free and roughness-free atomic layer neutral beam etching (NBE) compared with one fabricated by conventional plasma etching (PE). The etching interface roughness and defect were estimated by high-resolution transmission electron microscopy (TEM). In the case of using atomic layer defect-free NBE, the root-mean-square roughness of the Ge Fin sidewall surface is 1/3 times smaller than that using PE. Then, the electron mobility of Ge FinFET was improved by 1.65 times compared with that of a PE etched FinFET sample. For the subthreshold swing, the defect density of the interface between the Ge and gate dielectric film was improved by NBE. Ioff average currents of NBE and PE were around 18.1 and 57.6 nA/μm, respectively. As a result, NBE reduces the off-leakage current to 1/3 times less than PE. This corresponded to the differences in surface roughness and defect generation between NBE and PE. Therefore, we found that NBE could achieve a good performance by defect-free and atomically-flat etching the surface.

Original languageEnglish
Article number9340551
Pages (from-to)26-30
Number of pages5
JournalIEEE Open Journal of Nanotechnology
Publication statusPublished - 2021


  • Field effect transistors
  • gate leakage
  • germanium
  • nanofabrication
  • surface roughness

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Electronic, Optical and Magnetic Materials
  • Materials Chemistry


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