A Novel Localized-Trapped-Charge-Induced Threshold Voltage Model for Double-Fin Multi-Channel FETs (DFMcFETs)

Abstract

With the effects of localized trapped charges on the flat-band voltage, a novel localized-trapped-charge-induced threshold voltage model for the double-fin multi-channel FET (DFMcFET) is presented based on the quasi-3-D scaling equation and minimum bottom-central potential. It is shown that the deep trench of the DFMcFET is superior to the shallow one in respect of reducing the localized-trapped-charge-induced threshold voltage degradation (LTTVD). Besides, the low drain voltage ${V_{\mathrm{ ds}}}$ , the low trapped charge density ${N_{f}}$ , the small damaged zone near the drain side ${L_{s}}$ and the thin gate oxide ${t_{\mathrm{ ox}}}$ are required to resist LTTVD as the normalized damaged zone is increased. The LTTVD can be well controlled by the scaling theory. With the fixed damaged zone and trapped charge density, the allowable minimum channel length can be uniquely determined according to the criterion of scaling factor. In comparison to the conventional FinFET, DFMcFET not only provides more conducting channel, but also suffers less threshold voltage degradation caused by the short-channel effects irrespective of trapped charge polarity. With its computational efficiency and simple form, the model can be easily used for the circuit application for DFMcFET.