Experimental study on electron mobility in ultrathin-body silicon-on-insulator metal-oxide-semiconductor field-effect transistors

Ken Uchida, Junji Koga, Shin Ichi Takagi

    Research output: Contribution to journalArticle

    71 Citations (Scopus)

    Abstract

    The electron mobility in ultrathin-body (UTB) silicon-on-insulator (SOI) metal-oxide-semiconductor field-effect transistors (MOSFETs) with SOI thicknesses from 2.3 to 60 nm is measured in a wide temperature range from 25 to 300 K. In UTB SOI MOSFETs with SOI thickness ranging from 5 to 20 nm, a monotonic decrease of electron mobility with a decrease in SOI thickness is observed at room temperature. At extremely low temperature (25 K), however, the electron mobility of UTB SOI MOSFETs with SOI thickness of 5.7 nm is not degraded but is almost the same as that of thick-body SOI MOSFETs. On the other hand, in UTB SOI MOSFETs with SOI thickness ranging from 3.5 to 4.5 nm, an increase of electron mobility with a decrease in SOI thickness is clearly demonstrated at the effective normal field of around 0.3 MVcm at 300 K. It is concluded that the decrease of electron mobility in SOI thickness ranging from 5 to 20 nm is due to the increased phonon scattering in thinner SOI films. The observed enhancement of electron mobility with decreasing SOI thickness from 4.5 to 3.5 nm is ascribed to the subband structure modulation induced by quantum confinement effects in nanoscale SOI films. The impact of SOI thickness fluctuations on electron mobility and the methods to evaluate the thickness of ultrathin SOI films are also discussed.

    Original languageEnglish
    Article number074510
    JournalJournal of Applied Physics
    Volume102
    Issue number7
    DOIs
    Publication statusPublished - 2007 Oct 22

    ASJC Scopus subject areas

    • Physics and Astronomy(all)

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