Proton-induced mobility degradation in finfets with stressor layers and strained SOI substrates

Daisuke Kobayashi, Eddy Simoen, Sofie Put, Alessio Griffoni, Marc Poizat, Kazuyuki Hirose, Cor Claeys

    Research outputpeer-review


    Proton irradiation effects on fin-type field effect transistors (FinFETs) are examined from the viewpoint of their electrical-performance parameter of mobility. They are fabricated with various types of combination of strain/stress techniques to control their mobilities. The base stress level is globally modified by means of nonstrained or strained silicon-on-insulator wafers. Some process splits, additionally, receive a local strain tuning with a contact-etch-stop layer (CESL). Both n - and p-type FinFETs are evaluated. A 60-MeV proton irradiation with a fluence of 1012 p/cm2 leads to mobility changes for wide-fin samples: degradation for n-type and enhancement for p-type. These mobility variations can be explained with a change in the number of charged interface traps at the Si and buried-oxide interface. Narrow-fin devices exhibit mobility changes unnoticeable statistically. A comparison with previous studies indicates an elevated source/drain structure plays a role in this mobility preservation. Although the mobility is kept intact in the narrow-fin samples, a close investigation based on a two channel-component model can reveal noticeable mobility variations at a component level. In this study, observed mobility changes are complex depending on the adopted stress techniques as well as process parameters and cannot be explained by the stress levels simply.

    Original languageEnglish
    Article number5720535
    Pages (from-to)800-807
    Number of pages8
    JournalIEEE transactions on nuclear Science
    Issue number3 PART 2
    StatePublished - Jun 2011

    ASJC Scopus subject areas

    • Nuclear and High Energy Physics
    • Nuclear Energy and Engineering
    • Electrical and Electronic Engineering

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