Open Access Nano Express

Si nanowires by a single-step metal-assisted chemical etching process on lithographically defined areas: formation kinetics

Androula Galiouna Nassiopoulou*, Violetta Gianneta and Charalambos Katsogridakis

Author Affiliations

Institute of Microelectronics (IMEL), National Center for Scientific Research (NCSR) Demokritos, Terma Patriarhou Gregoriou, Aghia Paraskevi, Athens, 15310, Greece

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Nanoscale Research Letters 2011, 6:597  doi:10.1186/1556-276X-6-597

Published: 16 November 2011

Abstract

In this paper, we investigate the formation kinetics of Si nanowires [SiNWs] on lithographically defined areas using a single-step metal-assisted chemical etching process in an aqueous HF/AgNO3 solution. We show that the etch rate of Si, and consequently, the SiNW length, is much higher on the lithographically defined areas compared with that on the non-patterned areas. A comparative study of the etch rate in the two cases under the same experimental conditions showed that this effect is much more pronounced at the beginning of the etching process. Moreover, it was found that in both cases, the nanowire formation rate is linear with temperature in the range from 20°C to 50°C, with almost the same activation energy, as obtained from an Arrhenius plot (0.37 eV in the case of non-patterned areas, while 0.38 eV in the case of lithographically patterned areas). The higher etch rate on lithographically defined areas is mainly attributed to Si surface modification during the photolithographic process.

PACS: 68; 68.65-k.

Keywords:
Si nanowires; metal-assisted chemical etching; lithographically defined areas; formation kinetics