Solution‐Processed Dual Gate Ferroelectric–Ferroelectric Organic Polymer Field‐Effect Transistor for the Multibit Nonvolatile Memory

Abstract

The stable multibit storage operation of solution‐processed organic nonvolatile memories (ONVMs) based on ferroelectric field‐effect transistors (FeFETs) for high density data storage devices are demonstrated. The proposed multibit ONVM structure consists of a p‐type polymer semiconductor sandwiched between poly(vinylidene fluoride‐trifluoroethylene) [P(VDF‐TrFE)] layers serving as ferroelectric gate insulators to form a dual gate ferroelectric–ferroelectric memory transistor (DG Fe‐FeMT). With the extra memory space created by the spatially separated ferroelectrics, a 2‐bit memory representation (“11”, “10”, “01” and “00”) with clear memory margins is achieved due to the bistability of each P(VDF‐TrFE) and the high performance of the polymer semiconductor. The distinct four‐level reading of memory output currents (IM,OUTs) results from the independent programming voltages of the dual gates. An excellent distinct six‐level IM,OUTs are also achieved in DG Fe‐FeMT using the intermediate programming voltages. Finally, the possibility of 3−bit, or 8 memory states, are demonstrated by optimizing the bistability and intermediate polarization states of the ferroelectrics without increasing the device area horizontally. The DG Fe‐FeMT has a great potential for cost−effective flexible nonvolatile multibit data storage devices due to its solution‐process and low annealing temperatures.

Dual-Ferroelectric-Coupling-Engineered Two-Dimensional Transistors for Multifunctional In-Memory Computing

“…Clearly, compared with the conventional single-gate FeFETs, rich ferroelectric-field-effect behaviors can be realized in the 2D FeFETs with the presented dual-ferroelectric-coupling effects. Note that the dual-gate FeFETs have been explored by previously focusing on two types of structures, i.e., (1) a double-ferroelectric gate and (2) one-ferroelectric–one-linear dielectric gate structure. , However, as constrained by the intrinsic properties of the channel materials (conventional bulk semiconductors), these devices normally were explored to demonstrate enhanced multilevel memory states but without the ability to perform any two-input Boolean logic functions . Moreover, using the linear dielectric gate would result in a volatile electrostatic control, which fails to get rid of the static power consumption. , Therefore, the presented working mechanism of our dual-gate 2D FeFET would hint at a different device operation principle that can efficiently address the above-mentioned limitations found in the conventional dual-gate FeFETs.…”

The Doping Effect on the Intrinsic Ferroelectricity in Hafnium Oxide-Based Nano-Ferroelectric Devices

“…Furthermore, the Al atoms entered the crystal lattice of the HfAlO thin films, which further enhanced the ferroelectricity. However, they belonged to the same o-phase, as observed from the asymmetric nature of the phase structure …”

“…However, they belonged to the same o-phase, as observed from the asymmetric nature of the phase structure. 26 To better explore the influence of Al content on the ferroelectric properties of the HfAlO thin films, the crystal structures of the thin films were physically characterized using X-ray diffraction (XRD) profiles. The acquired XRD profiles were used to identify the crystalline phases, including o-and m-phases, which influenced the HfAlO thin films.…”

Hybrid Ferroelectric P(VDF-TrFE)/BZT Insulators for Pentacene-Based Nonvolatile Memory Applications

“…O RGANIC ferroelectric poly (vinylidene fluoride/ trifluoroethylene) [P(VDF/TrFE)] copolymer has recently attracted attention for nonvolatile memory applications because of its large remnant polarization and ease of fabrication in thin films formed through solution process at low temperatures [1]- [6]. However, P(VDF/TrFE) copolymers contain intrinsic defects caused by imperfect chain configuration, heterogeneous crystalline-amorphous boundaries, grain-grain mismatches, and residual solvent.…”

“…However, P(VDF/TrFE) copolymers contain intrinsic defects caused by imperfect chain configuration, heterogeneous crystalline-amorphous boundaries, grain-grain mismatches, and residual solvent. These defects normally impede the low voltage operation and leakage current [1]. In ferroelectric FET (FeFET) memory devices, the interlayer serves as the insulator that prevents leakage between the gate and the drain [3], [6].…”