Highly anisotropic gate electrode patterning in neutral beam etching using F2 gas chemistry

Shuichi Noda, Yasuyuki Hoshino, Takuya Ozaki, Seiji Samukawa

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)

Abstract

Pure F2 gas chemistry was evaluated in comparison with SF6 and Cl2 gas chemistries for etching poly-Si gates of metal-oxide-semiconductor field effect transistors in our neutral beam source. In the case of SF6 gas chemistry, the polycrystalline silicon (poly-Si) etch rate was high enough, whereas a large side etching was observed. In the case of Cl2 gas chemistry, the pattern profile was anisotropic, but the etch rate was very low. The tradeoff was caused by differences in the etching reactivity of F and Cl radicals with the poly-Si. Though the SF6 -based neutral beam caused a large side etching due to diffused F radicals, an anisotropic profile was obtained by using the F2 -based neutral beam, and the etch rate was much larger than that in the Cl2 gas chemistry. These notable characteristics were accomplished by suppressing excessive dissociation of F radicals and by generating large amount of negative F ions in a pulse-time-modulated F2 plasma in the neutral beam source.

Original languageEnglish
Pages (from-to)2063-2068
Number of pages6
JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
Volume23
Issue number5
DOIs
Publication statusPublished - 2005

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Electrical and Electronic Engineering

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