Nanofabrication of high aspect ratio (∼50:1) sub-10 nm silicon nanowires using inductively coupled plasma etching

Mirza, M. M. , Zhou, H., Velha, P., Li, X. , Docherty, K. E., Samarelli, A., Ternent, G. and Paul, D. J. (2012) Nanofabrication of high aspect ratio (∼50:1) sub-10 nm silicon nanowires using inductively coupled plasma etching. Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, 30(6), 06FF02. (doi:10.1116/1.4755835)

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Abstract

The development of nanofabrication techniques for creating high aspect ratio (∼50:1) sub-10 nm silicon nanowires (SiNWs) with smooth, uniform, and straight vertical sidewalls using an inductively coupled plasma (ICP) etching process at 20°C is reported. In particular, to improve the quality and flexibility of the pattern transfer process for high aspect ratio SiNWs, hydrogen silsesquioxane, a high-resolution, inorganic, negative-tone resist for electron-beam lithography has been used as both the resist for defining sub-10 nm patterns and the hard mask for etching the underneath silicon material. The effects of SF6/C4F8 gas flow rates, chamber pressure, platen power and ICP power on the etch rate, selectivity, and sidewall profile are investigated. To minimize plasma-induced sidewall damage, moderate plasma excitation power (ICP power of 600 W) and low ion energy (platen power of 6–12 W) were used. Using the optimized etch process at room temperature (20°C), the authors have successfully fabricated sub-10 nm SiNWs, which have smooth vertical sidewall profile and aspect ratios up to ˜50:1. This optimized etch combined with a controlled thermal oxidation allows the realization of consistent, reproducible, and reliable SiNW devices with nominal widths from 100 nm down to sub-5 nm in silicon on top of SiO2 fabricated on silicon on insulator substrates.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Docherty, Mr Kevin and Li, Dr Xu and Mirza, Dr Muhammad M A and Zhou, Dr Haiping and Velha, Mr Philippe and Paul, Professor Douglas and Ternent, Dr Gary and Samarelli, Mr Antonio
Authors: Mirza, M. M., Zhou, H., Velha, P., Li, X., Docherty, K. E., Samarelli, A., Ternent, G., and Paul, D. J.
College/School:College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
Research Group:Semiconductor Device Group and James Watt Nanofabrication Centre
Journal Name:Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
ISSN:2166-2746
ISSN (Online):1520-8567
Published Online:27 September 2012

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