Atomic layer germanium etching for 3D Fin-FET using chlorine neutral beam

Daisuke Ohori, Takuya Fujii, Shuichi Noda, Wataru Mizubayashi, Kazuhiko Endo, En-Tzu Lee, Yi-Ming Li, Yao-Jen Lee, Takuya Ozaki, Seiji Samukawa*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

15 Scopus citations


In case of using pure chlorine chemistry, Ge etching reactivity is three times higher than Si etching reactivity because of the larger lattice spacing in Ge. As a result, during the chlorine plasma etching of a Ge Fin structure, there are serious problems such as a large side-etching and large surface roughness on the Ge sidewall. Conversely, the authors found that several-ten nanometer-width Ge Fin structures with defect-free, vertical, and smooth sidewalls were successively delineated by chlorine neutral beam etching. Based on these results, the problems caused by chlorine plasma etching are considered to be due to the enhancement of chemical reactivity caused by defect on the sidewall with the irradiation of ultraviolet/vacuum ultra violet (UV/VUV) photons. Namely, it is clarified that the neutral beam etching could achieve real atomic layer etching by controlling the defect without any UV/VUV photons on the sidewall surface for future nanoscale Ge Fin structures. Published by the AVS.

Original languageEnglish
Article number021003
Pages (from-to)1-5
Number of pages5
JournalJournal of Vacuum Science and Technology A
Issue number2
StatePublished - Mar 2019




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