Search

Ferroelectric (FE) materials are being studied for a variety of applications in memory, logic, and neuromorphic computing, for which predictive models of FE polarization are essential. In this paper, we present a Monte Carlo simulation framework capable of predicting the dynamic, history-dependent response of an FE under arbitrary input waveforms. The simulation is developed by generalizing the physics-based nucleation-limited switching model for polarization reversal in a polycrystalline FE. Measured polarization reversal data from fabricated FE Hf0.5Zr0.5O2 capacitors are used to extract the statistical distribution of FE grains. After parameter extraction, the model is able to predict the dynamics of the FE capacitor without further calibration. Finally, the model is applied to characterize the dynamic response of FE–dielectric bilayer structures and quantify the reduction in memory window due to device variability. [ABSTRACT FROM AUTHOR]

Ferroelectric Zr-doped HfO2 (HZO) is a promising candidate for steep slope transistors and memory technology. For these applications, it is essential to understand and optimize the switching dynamics of the ferroelectric film. In this letter, we characterize the polarization reversal of an 8 nm-thick HZO film deposited by the atomic layer deposition with voltage pulses varying in amplitude (0.8–2 V) and duration (200 ns–7.6 ms). We show that the measurements are well described by a nucleation limited switching model, which enables extraction of the minimum switching time and the probability distribution of local electric field variations in the polycrystalline film. The close model fit spanning 5 orders of magnitude in pulse duration indicates the applicability of this model to HZO. This characterization framework can be used to quantify, compare, and optimize the switching dynamics of ferroelectric HZO. [ABSTRACT FROM AUTHOR]

Track-and-hold (T&H) circuits are used in a variety of applications. Noise is a key parameter in a T&H and can be traded for settling time or power consumption. The classical T&H noise design methodology considers only white noise sources, neglecting low-frequency noise sources. Although low-frequency noise contributions have been analyzed in the literature, an insightful, design-oriented analysis for flicker noise that can also be extended for arbitrary noise sources has not been proposed yet. In this brief, we present a time-domain noise analysis for a charge-redistribution T&H circuit. The analysis considers the noise contribution from white and 1/f sources. A design-oriented expression to compute the excess noise power due to flicker noise, as a function of the sampling rate, the intended T&H resolution, and the noise parameters, is obtained. This expression shows the dependence of the relative contribution of flicker noise over white noise, on the T&H design parameters. A simplified expression allows one to assess the relative contribution of flicker noise during an early stage of the design flow. [ABSTRACT FROM PUBLISHER]

A back-gated multilayer nanoribbon molybdenum disulfide (MoS2) transistor grown by chemical vapor transport and doped using polyethylene oxide cesium perchlorate is fabricated and characterized. Ions in the polymer dielectric are directed by side gates to the source and drain access regions where they form electric double layers (EDLs) that control the carrier densities. This allows the junctions of the same transistor channel to be reconfigured as an n-MOSFET, p-MOSFET, and as a tunnel field-effect transistors. The EDLs are formed at room temperature and then locked into place by cooling the polymer below the glass transition temperature (~240 K). Transport measurements are presented and explained using simulated band diagrams. Both n and p-conduction in MoS2 is demonstrated using solid polymer ion doping, enabling characterization of a semiconductor in which the doping of the same channel has been reconfigured to form three different transistor configurations. [ABSTRACT FROM AUTHOR]