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",
    year = "2014",
    doi = "10.1117/1.JMM.13.1.013010",
    language = "English",
    volume = "13",
    journal = "Journal of Micro/ Nanolithography, MEMS, and MOEMS",
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    publisher = "International Society for Optics and Photonics SPIE",
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    TY - JOUR

    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

    IS - 1

    ER -