Passivation of Ge/high-κ interface using RF Plasma nitridation

Ghada Dushaq, Ammar Nayfeh, Mahmoud Rasras

    Research output: Contribution to journalArticle

    Abstract

    In this paper, plasma nitridation of a germanium surface using NH3 and N2 gases is performed with a standard RF-PECVD method at a substrate temperature of 250 °C. The structural and optical properties of the Ge surface have been investigated using Atomic Force Microscopy (AFM), Fourier Transform Infrared Spectroscopy (FT-IR), and Variable Angle Spectroscopic Ellipsometery (VASE). Study of the Ge (100) surface revealed that it is nitrated after plasma treatment while the GeO2 regrowth on the surface has been suppressed. Also, stability of the treated surface under air exposure is observed, where all the measurements were performed at room ambient. The electrical characteristics of fabricated Al/Ti/HfO2/GeON/p-Ge capacitors using the proposed surface treatment technique have been investigated. The C-V curves indicated a negligible hysteresis compared to ∼500 mV observed in untreated samples. Additionally, the C-V characteristic is used to extract the high-κ/Ge interface trap density using the most commonly used methods in determining the interface traps. The discussion includes the Dit calculation from the high-low frequency (Castagné-Vapaille) method and Terman (high-frequency) method. The high-low frequency method indicated a low interface trap density of ∼2.5 ×1011 eV-1.cm-2 compared to the Terman method. The J-V measurements revealed more than two orders of magnitude reduction of the gate leakage. This improved Ge interface quality is a promising low-temperature technique for fabricating high-performance Ge MOSFETs.

    Original languageEnglish (US)
    Article number015003
    JournalSemiconductor Science and Technology
    Volume33
    Issue number1
    DOIs
    StatePublished - Jan 1 2018

    Fingerprint

    Nitridation
    Passivation
    passivity
    Plasmas
    traps
    Germanium
    low frequencies
    Plasma enhanced chemical vapor deposition
    surface treatment
    rooms
    Fourier transform infrared spectroscopy
    Hysteresis
    Surface treatment
    Structural properties
    Atomic force microscopy
    germanium
    capacitors
    Capacitors
    leakage
    field effect transistors

    Keywords

    • Ge/high k interfaces
    • germanium MOSCAP
    • plasma nitridation

    ASJC Scopus subject areas

    • Electronic, Optical and Magnetic Materials
    • Condensed Matter Physics
    • Electrical and Electronic Engineering
    • Materials Chemistry

    Cite this

    Passivation of Ge/high-κ interface using RF Plasma nitridation. / Dushaq, Ghada; Nayfeh, Ammar; Rasras, Mahmoud.

    In: Semiconductor Science and Technology, Vol. 33, No. 1, 015003, 01.01.2018.

    Research output: Contribution to journalArticle

    Dushaq, Ghada ; Nayfeh, Ammar ; Rasras, Mahmoud. / Passivation of Ge/high-κ interface using RF Plasma nitridation. In: Semiconductor Science and Technology. 2018 ; Vol. 33, No. 1.
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