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The current behaviors of fully depleted (FD) symmetric double-gate (DG) metal-oxide-semiconductor field effect transistors (MOSFETs) with doped short-channel were parametrically modeled with the simple closed-form in all operational regions. In the diffusion current model, a physical parameter D G as a function of gate bias (V GS ), drain bias (V DS ), silicon body width (W B ), channel length (L), and channel doping concentration (N b ) was introduced to consider the V GS dependence. Also, the subthreshold slope (SS) of DG MOSFETs with doped channel was modeled accurately with D G . D D which is dependent on V DS was introduced to consider the drain-induced barrier lowering (DIBL) in the diffusion current model. After the strong inversion, the drift current of doped DG MOSFETs was modeled by considering inversion-layer capacitance based on chargesheet approximation. The channel length modulation by V DS was considered for accuracy in the current modeling of DG MOSFETs with doped short-channel. Our simple compact models predicted accurately DC characteristics of the devices with the channel length to 20 nm and shown good agreement with two-dimensional (2D) simulation.

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The diffusion current of fully depleted (FD) nanoscale surrounding-gate (SG) metal-oxide-semiconductor field effect transistors (MOSFETs) with a doped channel was physically modeled with a simple closed form based on the surface potential. The potential distribution [È x ðzÞ] of doped SG MOSFETs was derived using Young's simple approximation from a two-dimensional (2D) Poisson's equation. In the diffusion current model, to consider the dependence on gate bias (V GS ) and drain bias (V DS ), parameters (D G and D D ) were introduced. In the saturation region, the drift current modeling of doped FD SG MOSFETs was easily performed from the derived current model in the linear region. The current of the devices in the transition region was also modeled with the simple closed form using the diffusion and drift current model. Our simple compact model accurately predicted the current behaviors of the devices with a channel length up to 20 nm and shown good agreement with three-dimensional (3D) simulation.

We proposed a new body-tied triple-gate fin-type field-effect transistor (bulk FinFET) which has different gate work-functions on the top-and side-channel regions. The effect of gate work-function on the characteristics of the bulk FinFETs was studied by using three-dimensional device simulator. By increasing the top-gate work-function (È TG ) at a fixed side-gate workfunction (È SG ) of the bulk FinFET, threshold voltage (V th ) increases and off-state leakage current (I off ) reduces significantly without increasing doping concentration of the fin body. The bulk FinFETs with the low body doping and the threshold voltage controlled by midgap-gate work-function shown very small dependence on the corner shape, but shown very poor short channel effect (SCE). It was also shown that devices with the V th controlled by body doping shows significant corner effect and the effect becomes small as the fin width decreases. By applying our approach, we could reduce the off-current by more than 10 times without increasing fin body doping concentration.