Effects of Oxygen, Nitrogen and Fluorine on the Crystallinity of Tungsten by Hot-Wire Assisted ALD

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    Abstract

    A heated tungsten filament (wire) is well known to generate atomic hydrogen (at-H) by catalytically cracking molecular hydrogen (H2) upon contact. This mechanism is employed in our work on hot-wire (HW) assisted atomic layer deposition (HWALD), a novel energy-enhancement technique. HWALD has been successfully utilized to deposit tungsten (W) films using alternating pulses of WF6 and at-H. Depending on the conditions, either low-resistivity α- or higher-resistivity β-crystalline phases of W can be obtained. This work aims to clarify (i) which factors are decisive for the formed crystal phase and (ii) the role of the residual gases in the film growth mechanism. In this light, the effects of adding impurities (N2O, O2, NH3 and H2O) were investigated. Oxidizing species have a retarding effect on W growth but the process can be re-initiated after stopping their supply. In contrast, nitridizing species have a permanent inhibition effect. Further, the effects of WF6 overdose were studied. The surplus of WF6 appeared to be crucial for the process: in many cases this led to the formation of β-phase W instead of the α-phase, with a memory effect lasting for several deposition runs. Extra fluorine-containing species were thus identified as the likely cause of β-phase formation.
    Original languageEnglish
    Pages (from-to)P839-P844
    JournalECS journal of solid state science and technology
    Volume6
    Issue number12
    DOIs
    Publication statusPublished - 6 Dec 2017
    EventEuroCVD 2017: Joint EuroCVD 21 – Baltic ALD 15 Conference - Konsert och Kongress venue , Linköping, Sweden
    Duration: 11 Jun 201714 Jun 2017
    http://www.eurocvd-balticald2017.se/

    Fingerprint

    Tungsten
    Fluorine
    Atomic layer deposition
    Hydrogen
    Tungsten deposits
    Nitrogen
    Wire
    Oxygen
    Film growth
    Gases
    Impurities
    Crystalline materials
    Data storage equipment
    Crystals

    Keywords

    • hot-wire ALD
    • Oxidation
    • Tungsten

    Cite this

    @article{c8e9c802bd8e4efc9cc952fa43d74954,
    title = "Effects of Oxygen, Nitrogen and Fluorine on the Crystallinity of Tungsten by Hot-Wire Assisted ALD",
    abstract = "A heated tungsten filament (wire) is well known to generate atomic hydrogen (at-H) by catalytically cracking molecular hydrogen (H2) upon contact. This mechanism is employed in our work on hot-wire (HW) assisted atomic layer deposition (HWALD), a novel energy-enhancement technique. HWALD has been successfully utilized to deposit tungsten (W) films using alternating pulses of WF6 and at-H. Depending on the conditions, either low-resistivity α- or higher-resistivity β-crystalline phases of W can be obtained. This work aims to clarify (i) which factors are decisive for the formed crystal phase and (ii) the role of the residual gases in the film growth mechanism. In this light, the effects of adding impurities (N2O, O2, NH3 and H2O) were investigated. Oxidizing species have a retarding effect on W growth but the process can be re-initiated after stopping their supply. In contrast, nitridizing species have a permanent inhibition effect. Further, the effects of WF6 overdose were studied. The surplus of WF6 appeared to be crucial for the process: in many cases this led to the formation of β-phase W instead of the α-phase, with a memory effect lasting for several deposition runs. Extra fluorine-containing species were thus identified as the likely cause of β-phase formation.",
    keywords = "hot-wire ALD, Oxidation, Tungsten",
    author = "Mengdi Yang and Aarnink, {Antonius A.I.} and Wolters, {Robertus A.M.} and Jurriaan Schmitz and Kovalgin, {Alexey Y.}",
    year = "2017",
    month = "12",
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    doi = "10.1149/2.0241712jss",
    language = "English",
    volume = "6",
    pages = "P839--P844",
    journal = "ECS journal of solid state science and technology",
    issn = "2162-8769",
    publisher = "The Electrochemical Society Inc.",
    number = "12",

    }

    TY - JOUR

    T1 - Effects of Oxygen, Nitrogen and Fluorine on the Crystallinity of Tungsten by Hot-Wire Assisted ALD

    AU - Yang, Mengdi

    AU - Aarnink, Antonius A.I.

    AU - Wolters, Robertus A.M.

    AU - Schmitz, Jurriaan

    AU - Kovalgin, Alexey Y.

    PY - 2017/12/6

    Y1 - 2017/12/6

    N2 - A heated tungsten filament (wire) is well known to generate atomic hydrogen (at-H) by catalytically cracking molecular hydrogen (H2) upon contact. This mechanism is employed in our work on hot-wire (HW) assisted atomic layer deposition (HWALD), a novel energy-enhancement technique. HWALD has been successfully utilized to deposit tungsten (W) films using alternating pulses of WF6 and at-H. Depending on the conditions, either low-resistivity α- or higher-resistivity β-crystalline phases of W can be obtained. This work aims to clarify (i) which factors are decisive for the formed crystal phase and (ii) the role of the residual gases in the film growth mechanism. In this light, the effects of adding impurities (N2O, O2, NH3 and H2O) were investigated. Oxidizing species have a retarding effect on W growth but the process can be re-initiated after stopping their supply. In contrast, nitridizing species have a permanent inhibition effect. Further, the effects of WF6 overdose were studied. The surplus of WF6 appeared to be crucial for the process: in many cases this led to the formation of β-phase W instead of the α-phase, with a memory effect lasting for several deposition runs. Extra fluorine-containing species were thus identified as the likely cause of β-phase formation.

    AB - A heated tungsten filament (wire) is well known to generate atomic hydrogen (at-H) by catalytically cracking molecular hydrogen (H2) upon contact. This mechanism is employed in our work on hot-wire (HW) assisted atomic layer deposition (HWALD), a novel energy-enhancement technique. HWALD has been successfully utilized to deposit tungsten (W) films using alternating pulses of WF6 and at-H. Depending on the conditions, either low-resistivity α- or higher-resistivity β-crystalline phases of W can be obtained. This work aims to clarify (i) which factors are decisive for the formed crystal phase and (ii) the role of the residual gases in the film growth mechanism. In this light, the effects of adding impurities (N2O, O2, NH3 and H2O) were investigated. Oxidizing species have a retarding effect on W growth but the process can be re-initiated after stopping their supply. In contrast, nitridizing species have a permanent inhibition effect. Further, the effects of WF6 overdose were studied. The surplus of WF6 appeared to be crucial for the process: in many cases this led to the formation of β-phase W instead of the α-phase, with a memory effect lasting for several deposition runs. Extra fluorine-containing species were thus identified as the likely cause of β-phase formation.

    KW - hot-wire ALD

    KW - Oxidation

    KW - Tungsten

    U2 - 10.1149/2.0241712jss

    DO - 10.1149/2.0241712jss

    M3 - Article

    VL - 6

    SP - P839-P844

    JO - ECS journal of solid state science and technology

    JF - ECS journal of solid state science and technology

    SN - 2162-8769

    IS - 12

    ER -