Compensation of oxygen defects in La-silicate gate dielectrics for improving effective mobility in high-k/metal gate MOSFET using oxygen annealing process

T. Kawanago, T. Suzuki, Y. Lee, K. Kakushima, P. Ahmet, K. Tsutsui, A. Nishiyama, N. Sugii, K. Natori, T. Hattori, H. Iwai

    Research output: Contribution to journalArticle

    9 Citations (Scopus)

    Abstract

    Oxygen incorporation for compensation of oxygen defects is investigated with La-silicate dielectrics in directly contacted with the Si substrate. The amount of oxygen is controlled by the temperature of annealing in oxygen atmosphere (oxygen annealing) and the thickness of the gate electrode. The positive shift in flatband voltage (V FB) by oxygen incorporation is an experimental evidence for defects compensation in La-silicate dielectrics. Optimum oxygen annealing provides the V FB shift toward positive direction without increasing equivalent oxide thickness (EOT). Although the oxygen annealing degrades the interfacial property at La-silicate/Si interface, subsequent forming gas annealing (FGA) can recover the interfacial property. It is experimentally revealed that the positive V FB shift of La-silicate dielectrics is stable even after subsequent FGA. The supplied oxygen in La-silicate is expected to maintain even after reducing process. Movement of Fermi level toward the Si valence band edge caused by oxygen incorporation is successfully observed by XPS. Moreover, no chemical reaction between La-silicate and Si substrate by oxygen annealing are confirmed from TEM observation and analyses of X-ray photoelectron spectra. It is experimentally demonstrated that effective hole mobility can be improved without increase in EOT by combination of oxygen annealing and FGA.

    Original languageEnglish
    Pages (from-to)68-72
    Number of pages5
    JournalSolid-State Electronics
    Volume68
    DOIs
    Publication statusPublished - 2012 Feb 1

    Keywords

    • Effective mobility
    • High-k gate dielectrics
    • Oxygen vacancy
    • Rare earth oxides
    • Silicate

    ASJC Scopus subject areas

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

    Fingerprint Dive into the research topics of 'Compensation of oxygen defects in La-silicate gate dielectrics for improving effective mobility in high-k/metal gate MOSFET using oxygen annealing process'. Together they form a unique fingerprint.

  • Cite this

    Kawanago, T., Suzuki, T., Lee, Y., Kakushima, K., Ahmet, P., Tsutsui, K., Nishiyama, A., Sugii, N., Natori, K., Hattori, T., & Iwai, H. (2012). Compensation of oxygen defects in La-silicate gate dielectrics for improving effective mobility in high-k/metal gate MOSFET using oxygen annealing process. Solid-State Electronics, 68, 68-72. https://doi.org/10.1016/j.sse.2011.10.006