Formation of ohmic contact to n-GaAs using (NH4)2S surface passivation

Eero Ristolainen, M. Puga-Lambers, B. Panthanay, Xia Holloway, Hannu Ronkainen, J. Saarilahti, V. Fisher, Kim Holloway

    Research output: Contribution to journalArticleScientificpeer-review

    Abstract

    Ohmic contacts between Au and sulfur‐passivated n‐GaAs have been formed without annealing after deposition of the metal. The GaAs samples doped with either 2×1016 or 3×1018 cm−3 Si were passivated with (NH4)2S in an aqueous solution, then the passivating sulfur was thermally desorbed in a vacuum. Desorption was followed immediately by in situ thermal evaporation of Au with the substrate at room temperature. Ohmic I‐V behavior was measured ex situ. C‐V measurements on a sample with a native oxide surface barrier layer showed the surface carrier concentration on the higher doped sample increased from 3×1018 to 7×1018 cm−3 after S desorption. Secondary ion mass spectroscopy data showed that S had diffused into the GaAs surface region. Thus S passivation prevented interfacial oxide formation during the exposure to air after the sample was passivated and before the vacuum chamber was pumped to a low pressure. Sulfur apparently diffused into the surface region during flash desorption in vacuum and increased the surface n‐doping concentration which led to ohmic contacts without post‐annealing of the Au films.
    Original languageEnglish
    Pages (from-to)1419-1421
    Number of pages3
    JournalJournal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures
    Volume12
    Issue number3
    DOIs
    Publication statusPublished - 1994
    MoE publication typeA1 Journal article-refereed

    Fingerprint

    Ohmic contacts
    Passivation
    Desorption
    Vacuum
    Sulfur
    Oxides
    Thermal evaporation
    Carrier concentration
    Spectroscopy
    Annealing
    Ions
    Substrates
    Air
    Metals
    Temperature

    Cite this

    Ristolainen, Eero ; Puga-Lambers, M. ; Panthanay, B. ; Holloway, Xia ; Ronkainen, Hannu ; Saarilahti, J. ; Fisher, V. ; Holloway, Kim. / Formation of ohmic contact to n-GaAs using (NH4)2S surface passivation. In: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures. 1994 ; Vol. 12, No. 3. pp. 1419-1421.
    @article{51eb460c41234247b75349950e8bc029,
    title = "Formation of ohmic contact to n-GaAs using (NH4)2S surface passivation",
    abstract = "Ohmic contacts between Au and sulfur‐passivated n‐GaAs have been formed without annealing after deposition of the metal. The GaAs samples doped with either 2×1016 or 3×1018 cm−3 Si were passivated with (NH4)2S in an aqueous solution, then the passivating sulfur was thermally desorbed in a vacuum. Desorption was followed immediately by in situ thermal evaporation of Au with the substrate at room temperature. Ohmic I‐V behavior was measured ex situ. C‐V measurements on a sample with a native oxide surface barrier layer showed the surface carrier concentration on the higher doped sample increased from 3×1018 to 7×1018 cm−3 after S desorption. Secondary ion mass spectroscopy data showed that S had diffused into the GaAs surface region. Thus S passivation prevented interfacial oxide formation during the exposure to air after the sample was passivated and before the vacuum chamber was pumped to a low pressure. Sulfur apparently diffused into the surface region during flash desorption in vacuum and increased the surface n‐doping concentration which led to ohmic contacts without post‐annealing of the Au films.",
    author = "Eero Ristolainen and M. Puga-Lambers and B. Panthanay and Xia Holloway and Hannu Ronkainen and J. Saarilahti and V. Fisher and Kim Holloway",
    year = "1994",
    doi = "10.1116/1.587311",
    language = "English",
    volume = "12",
    pages = "1419--1421",
    journal = "Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics",
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    }

    Ristolainen, E, Puga-Lambers, M, Panthanay, B, Holloway, X, Ronkainen, H, Saarilahti, J, Fisher, V & Holloway, K 1994, 'Formation of ohmic contact to n-GaAs using (NH4)2S surface passivation', Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, vol. 12, no. 3, pp. 1419-1421. https://doi.org/10.1116/1.587311

    Formation of ohmic contact to n-GaAs using (NH4)2S surface passivation. / Ristolainen, Eero; Puga-Lambers, M.; Panthanay, B.; Holloway, Xia; Ronkainen, Hannu; Saarilahti, J.; Fisher, V.; Holloway, Kim.

    In: Journal of Vacuum Science and Technology B: Microelectronics and Nanometer Structures, Vol. 12, No. 3, 1994, p. 1419-1421.

    Research output: Contribution to journalArticleScientificpeer-review

    TY - JOUR

    T1 - Formation of ohmic contact to n-GaAs using (NH4)2S surface passivation

    AU - Ristolainen, Eero

    AU - Puga-Lambers, M.

    AU - Panthanay, B.

    AU - Holloway, Xia

    AU - Ronkainen, Hannu

    AU - Saarilahti, J.

    AU - Fisher, V.

    AU - Holloway, Kim

    PY - 1994

    Y1 - 1994

    N2 - Ohmic contacts between Au and sulfur‐passivated n‐GaAs have been formed without annealing after deposition of the metal. The GaAs samples doped with either 2×1016 or 3×1018 cm−3 Si were passivated with (NH4)2S in an aqueous solution, then the passivating sulfur was thermally desorbed in a vacuum. Desorption was followed immediately by in situ thermal evaporation of Au with the substrate at room temperature. Ohmic I‐V behavior was measured ex situ. C‐V measurements on a sample with a native oxide surface barrier layer showed the surface carrier concentration on the higher doped sample increased from 3×1018 to 7×1018 cm−3 after S desorption. Secondary ion mass spectroscopy data showed that S had diffused into the GaAs surface region. Thus S passivation prevented interfacial oxide formation during the exposure to air after the sample was passivated and before the vacuum chamber was pumped to a low pressure. Sulfur apparently diffused into the surface region during flash desorption in vacuum and increased the surface n‐doping concentration which led to ohmic contacts without post‐annealing of the Au films.

    AB - Ohmic contacts between Au and sulfur‐passivated n‐GaAs have been formed without annealing after deposition of the metal. The GaAs samples doped with either 2×1016 or 3×1018 cm−3 Si were passivated with (NH4)2S in an aqueous solution, then the passivating sulfur was thermally desorbed in a vacuum. Desorption was followed immediately by in situ thermal evaporation of Au with the substrate at room temperature. Ohmic I‐V behavior was measured ex situ. C‐V measurements on a sample with a native oxide surface barrier layer showed the surface carrier concentration on the higher doped sample increased from 3×1018 to 7×1018 cm−3 after S desorption. Secondary ion mass spectroscopy data showed that S had diffused into the GaAs surface region. Thus S passivation prevented interfacial oxide formation during the exposure to air after the sample was passivated and before the vacuum chamber was pumped to a low pressure. Sulfur apparently diffused into the surface region during flash desorption in vacuum and increased the surface n‐doping concentration which led to ohmic contacts without post‐annealing of the Au films.

    U2 - 10.1116/1.587311

    DO - 10.1116/1.587311

    M3 - Article

    VL - 12

    SP - 1419

    EP - 1421

    JO - Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics

    JF - Journal of Vacuum Science and Technology B: Nanotechnology and Microelectronics

    SN - 2166-2746

    IS - 3

    ER -