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In this paper we numerically examine the electrical characteristics of surrounding-gate strained silicon nanowire field effect transistors (FETs) by changing the radius (R SiGe ) of silicon-germanium (SiGe) wire. Due to the higher electron mobility, the n-type FETs with strained silicon channel films do enhance driving capability (∼8% increment on the drain current) in comparison with the pure Si one. The leakage current and transfer characteristics, the threshold-voltage (V t ), the drain induced barrier height lowering (DIBL), and the gate capacitance (C G ) are estimated with respect to different gate length (L G ), gate bias (V G ), and R SiGe . For short channel effects, such as V t roll-off and DIBL, the surrounding-gate strained silicon nanowire FET sustains similar characteristics with the pure Si one.

Thin tunneling oxides grown on a CF 4 pretreated silicon substrate were prepared and investigated for the first time. The tunneling current of the CF 4 -treated oxide is about three orders of magnitude higher than that of thermal oxide; furthermore, the stressinduced anomalous current and low electric field leakage current were greatly suppressed. The improvement was attributed to the incorporation of fluorine in the oxide region. Both control and CF 4 -treated devices exhibited comparable channel mobility. However, pretreatment with CF 4 markedly improved the reliability of the insulator. This oxide is highly promising for fabricating low-voltage electrically erasable and programmable read-only memories ͑EEPROMs͒ without increasing the complexity of the process.

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High tunneling current and large resistance against stress were the main issue of tunnel oxide for scaling down the operation voltage of EEPROMs. In this letter, thin-tunnel oxides grown on a CF 4 pretreated silicon substrate were prepared and investigated for the first time. The fabricated oxide has about three orders of tunneling current higher than that of control one; furthermore, the stress induced anomalous and low electric field leakage currents were greatly suppressed. The improvement could be contributed to F-incorporation in oxide. This type of oxide is suitable for fabricating low-voltage EEPROMs and less process complexity was added.Index Terms-Anomalous current, CF 4 fluorinated oxide, lowvoltage EEPROM, plasma pretreatment, SILC, tunnel oxide.