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The potential for negative-capacitance field-effect transistors (NCFETs) to enhance the unity-current-gain cutoff frequency ${f}_{T}$ and ${g}_{m}{f}_{T}/{I}_{D}$ ratio through a technique that mitigates the impacts of extrinsic parasitic capacitances is investigated, where ${g}_{m}$ is the transconductance and ${I}_{D}$ is the dc drain current and where “extrinsic” refers to elements arising outside an “intrinsic” or core transistor structure. We explain the technique and show that NCFETs can provide significant gains in extrinsic ${f}_{T}$ and ${g}_{m}{f}_{T}/{I}_{D}$ from this mitigation effect. However, an inherent degradation of intrinsic ${f}_{T}$ needs to be addressed to maximize these benefits, and this degradation can be alleviated through channel-length scaling as well as supply- and threshold-voltage tuning. The relative influences of different extrinsic parasitic elements are also evaluated, and it is found that improvements to ${f}_{T}$ and ${g}_{m}{f}_{T}/{I}_{D}$ increase as extrinsic parasitic capacitance increases and decrease as extrinsic parasitic resistance increases. Overall, this work finds that NCFET structures are promising candidates to mitigate the impacts of extrinsic parasitics in aggressively scaled transistors for the next-generation RF applications. [ABSTRACT FROM AUTHOR]

We propose a parallel negative-capacitance field-effect transistor (P-NCFET) structure, in which a ferroelectric operating in its negative-capacitance region is placed in parallel with the gate and source terminals of a MOSFET. The P-NCFET is stabilized by combining careful matching of the ferroelectric with the gate capacitance along with simple feedback realized using current mirrors. The novel stabilization approach opens the possibility for a variety of new applications that exploit the negative capacitance of ferroelectrics to cancel capacitance in integrated circuits. As an example, we show the P-NCFET structure has a significantly higher unity-current-gain frequency ${f}_{T}$ compared to a conventional MOSFET. [ABSTRACT FROM AUTHOR]

Recently, negative-capacitance FETs (NCFETs) have been proposed to reduce subthreshold slope and help continue supply-voltage scaling alongside channel-length scaling. We investigate the high-frequency switching behavior of NCFETs using the Landau–Khalatnikov equation to model ferroelectric materials. Multidomain interactions in the ferroelectric are considered, resulting in strong agreement with experimental measurements. Operation of NCFETs at gigahertz frequencies is investigated with this experimentally validated multidomain model. We find that the effectiveness of the voltage amplification in NCFETs is strongly dependent on the viscosity coefficient $\rho $ of the ferroelectric, and that a low \rho $ ( <0.1~\Omega \cdot \text {m} ) is required for the operation at the high gigahertz frequencies. [ABSTRACT FROM PUBLISHER]