Porosity control in metal-assisted chemical etching of degenerately doped silicon nanowires

Karthik Balasundaram, Jyothi S. Sadhu, Jae Cheol Shin, Bruno Azeredo, Debashis Chanda, Mohammad Malik, Keng Hsu, John A. Rogers, Placid Ferreira, Sanjiv Sinha, Xiuling Li

Research output: Contribution to journalArticle

88 Citations (Scopus)

Abstract

We report the fabrication of degenerately doped silicon (Si) nanowires of different aspect ratios using a simple, low-cost and effective technique that involves metal-assisted chemical etching (MacEtch) combined with soft lithography or thermal dewetting metal patterning. We demonstrate sub-micron diameter Si nanowire arrays with aspect ratios as high as 180:1, and present the challenges in producing solid nanowires using MacEtch as the doping level increases in both p- and n-type Si. We report a systematic reduction in the porosity of these nanowires by adjusting the etching solution composition and temperature. We found that the porosity decreases from top to bottom along the axial direction and increases with etching time. With a MacEtch solution that has a high [HF]:[H 2O 2] ratio and low temperature, it is possible to form completely solid nanowires with aspect ratios of less than approximately 10:1. However, further etching to produce longer wires renders the top portion of the nanowires porous.

Original languageEnglish (US)
Article number305304
JournalNanotechnology
Volume23
Issue number30
DOIs
StatePublished - Aug 3 2012
Externally publishedYes

Fingerprint

Silicon
Nanowires
Etching
Porosity
Metals
Aspect ratio
Lithography
Doping (additives)
Wire
Fabrication
Temperature
Chemical analysis
Costs

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Electrical and Electronic Engineering
  • Mechanical Engineering
  • Mechanics of Materials
  • Materials Science(all)

Cite this

Porosity control in metal-assisted chemical etching of degenerately doped silicon nanowires. / Balasundaram, Karthik; Sadhu, Jyothi S.; Shin, Jae Cheol; Azeredo, Bruno; Chanda, Debashis; Malik, Mohammad; Hsu, Keng; Rogers, John A.; Ferreira, Placid; Sinha, Sanjiv; Li, Xiuling.

In: Nanotechnology, Vol. 23, No. 30, 305304, 03.08.2012.

Research output: Contribution to journalArticle

Balasundaram, K, Sadhu, JS, Shin, JC, Azeredo, B, Chanda, D, Malik, M, Hsu, K, Rogers, JA, Ferreira, P, Sinha, S & Li, X 2012, 'Porosity control in metal-assisted chemical etching of degenerately doped silicon nanowires', Nanotechnology, vol. 23, no. 30, 305304. https://doi.org/10.1088/0957-4484/23/30/305304
Balasundaram, Karthik ; Sadhu, Jyothi S. ; Shin, Jae Cheol ; Azeredo, Bruno ; Chanda, Debashis ; Malik, Mohammad ; Hsu, Keng ; Rogers, John A. ; Ferreira, Placid ; Sinha, Sanjiv ; Li, Xiuling. / Porosity control in metal-assisted chemical etching of degenerately doped silicon nanowires. In: Nanotechnology. 2012 ; Vol. 23, No. 30.
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