Wet etching silicon nanofins with (111)-oriented sidewalls

Lianci Liu, Vladimir V. Kuryatkov, Sergey A. Nikishin, H. Rusty Harris, Mark Holtz

Research output: Contribution to journalArticle

Abstract

A systematic study of the chemical etching of Si(111) fins is reported. Optimized wet etching of Si(110) with isopropyl alcohol and tetramethyl ammonium hydroxide produces 30 nm wide silicon nanofins with (111)-oriented sidewalls. The addition of a sacrificial silicon wafer for doping the etchant reduces the surface roughness of the interfin region. Atomic force microscopy indicates interfin roughness of 2 nm (root-mean square) based on scan areas of 5 μm × 5 μm. The addition of a commercial surfactant helps in reducing the presence of shoulders where the (111) and (110) crystallographic surfaces meet. Smooth sidewalls are obtained as a consequence of the directional etching process. Using electron-beam lithography and SiO2 as a hard mask, fin aspect ratio of >8:1 with 30 nm wide fins is achieved.

Original languageEnglish
Article number021801
JournalJournal of Vacuum Science and Technology B:Nanotechnology and Microelectronics
Volume31
Issue number2
DOIs
StatePublished - Mar 2013

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