Smooth silicon sidewall etching for waveguide structures using a modified Bosch process

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Abstract

We present a method to etch vertical and smooth silicon sidewalls. The so-called modified Bosch process combines a passivation step, a breakthrough step, and an anisotropic etch step within one repeatable loop. Thanks to the sidewall protection from the passivation step and the anisotropic nature of the etch step, this method can etch smoother silicon sidewalls than either a typical Bosch process or a continuous anisotropic etch process. The silicon sidewall of a 4-ìm-deep waveguide structure etched by this method has a root mean square roughness below 10 nm and a peak-to-valley (P-V) roughness below 60 nm. Comparisons between silicon waveguides etched by this process and by another deep reactive-ion etching process showed remarkable improvement in propagation loss at the wavelength of 1550 nm.
Original languageEnglish
Number of pages6
JournalJournal of Micro/ Nanolithography, MEMS, and MOEMS
Volume13
Issue number1
DOIs
Publication statusPublished - 2014
MoE publication typeA1 Journal article-refereed

Fingerprint

Silicon
Etching
Waveguides
etching
waveguides
silicon
Passivation
Surface roughness
passivity
roughness
Reactive ion etching
valleys
Wavelength
propagation
wavelengths
ions

Keywords

  • Bosch process
  • deep reactive-ion etching
  • MEMS
  • MOEMS
  • sidewall roughness
  • silicon waveguides

Cite this

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title = "Smooth silicon sidewall etching for waveguide structures using a modified Bosch process",
abstract = "We present a method to etch vertical and smooth silicon sidewalls. The so-called modified Bosch process combines a passivation step, a breakthrough step, and an anisotropic etch step within one repeatable loop. Thanks to the sidewall protection from the passivation step and the anisotropic nature of the etch step, this method can etch smoother silicon sidewalls than either a typical Bosch process or a continuous anisotropic etch process. The silicon sidewall of a 4-{\`i}m-deep waveguide structure etched by this method has a root mean square roughness below 10 nm and a peak-to-valley (P-V) roughness below 60 nm. Comparisons between silicon waveguides etched by this process and by another deep reactive-ion etching process showed remarkable improvement in propagation loss at the wavelength of 1550 nm.",
keywords = "Bosch process, deep reactive-ion etching, MEMS, MOEMS, sidewall roughness, silicon waveguides",
author = "Feng Gao and Sami Ylinen and Markku Kainlauri and Markku Kapulainen",
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language = "English",
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T1 - Smooth silicon sidewall etching for waveguide structures using a modified Bosch process

AU - Gao, Feng

AU - Ylinen, Sami

AU - Kainlauri, Markku

AU - Kapulainen, Markku

PY - 2014

Y1 - 2014

N2 - We present a method to etch vertical and smooth silicon sidewalls. The so-called modified Bosch process combines a passivation step, a breakthrough step, and an anisotropic etch step within one repeatable loop. Thanks to the sidewall protection from the passivation step and the anisotropic nature of the etch step, this method can etch smoother silicon sidewalls than either a typical Bosch process or a continuous anisotropic etch process. The silicon sidewall of a 4-ìm-deep waveguide structure etched by this method has a root mean square roughness below 10 nm and a peak-to-valley (P-V) roughness below 60 nm. Comparisons between silicon waveguides etched by this process and by another deep reactive-ion etching process showed remarkable improvement in propagation loss at the wavelength of 1550 nm.

AB - We present a method to etch vertical and smooth silicon sidewalls. The so-called modified Bosch process combines a passivation step, a breakthrough step, and an anisotropic etch step within one repeatable loop. Thanks to the sidewall protection from the passivation step and the anisotropic nature of the etch step, this method can etch smoother silicon sidewalls than either a typical Bosch process or a continuous anisotropic etch process. The silicon sidewall of a 4-ìm-deep waveguide structure etched by this method has a root mean square roughness below 10 nm and a peak-to-valley (P-V) roughness below 60 nm. Comparisons between silicon waveguides etched by this process and by another deep reactive-ion etching process showed remarkable improvement in propagation loss at the wavelength of 1550 nm.

KW - Bosch process

KW - deep reactive-ion etching

KW - MEMS

KW - MOEMS

KW - sidewall roughness

KW - silicon waveguides

U2 - 10.1117/1.JMM.13.1.013010

DO - 10.1117/1.JMM.13.1.013010

M3 - Article

VL - 13

JO - Journal of Micro/ Nanolithography, MEMS, and MOEMS

JF - Journal of Micro/ Nanolithography, MEMS, and MOEMS

SN - 1932-5150

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