Origin of Negative Capacitance Transient in Ultrascaled Multidomain Metal-Ferroelectric-Metal Stack and Hysteresis-Free Landau Transistor

Harnessing the negative capacitance transient (NCT) in ferroelectric (FE) materials is a relatively new concept in nanoelectronics. In this article, a set of coupled equations based on Kirchhoff’s law, electrostatics, and an experimentally validated multidomain Landau–Khalatnikov (MD-LK) equation is used to simulate poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)]-based resistor-metal-FE-metal ( ${R}$ -MFM) series circuit in Synopsys technology computer-aided design. We show that the proposed MD MFM stack’s coercivity is reduced by 80.36%–89% concerning different oxide FEs. Unlike oxide FE-based gate stacks, the P(VDF-TrFE)-based ${R}$ -MFM series circuit can exploit the NCT effect at lower supply voltages ( ${V}_{IN} =0.5$ V), with only 0.14 fJ of energy usage. We show that NCT in an ${R}$ -MFM series circuit originates from the mismatch in switching rate between the metal electrode free charge ( ${Q}_{FE}$ ) and the polarization ( ${P}$ ) in MD MFM during switching. The NC region of the FE thermodynamic energy profile causes the transient mismatch between ${Q}_{FE}$ and ${P}$ . Furthermore, it is validated using a bipolar to unipolar pulsing technique, which confirms that the underlying mechanism of NCT is directly related to ${P}$ switching and not to any extrinsic flaws in the system. The NCT response induced by the ${Q}_{FE}$ and ${P}$ mismatch is justified by its dependence on ${R}$ , viscosity coefficient, ${V}_{IN}$ , and the number of domains ( ${N}$ ). A hysteresis-free MD MFM-gated Landau transistor (LT) with a subthreshold swing (SS) of 26.59 mV/decade, OFF-state current of 8.64 nA/ $\mu \text{m}$ , and a high ON/OFF current switching ratio of $2\times10$ 5 is implemented. Integrating P(VDF-TrFE) as FE material allows SS to reduce by 15.43%–50.76% compared to earlier results. Moreover, the influence of ${N}$ and remanent ${P}$ ( ${P}_{r}$ ) on MD MFM-gated LT switching characteristics is discussed. Finally, an MD MFM-gated LT-based CMOS inverter is implemented for high-speed and low-power digital integrated circuit (IC) applications.