Reconfigurable Multifunctional van der Waals Ferroelectric Devices and Logic Circuits

Abstract

Emerging reconfigurable devices are fast gaining popularity in the search for next-generation computing hardware, while ferroelectric engineering of the doping state in semiconductor materials has the potential to offer alternatives to traditional von-Neumann architecture. In this work, we combine these concepts and demonstrate the suitability of reconfigurable ferroelectric field-effect transistors (Re-FeFETs) for designing nonvolatile reconfigurable logic-in-memory circuits with multifunctional capabilities. Modulation of the energy landscape within a homojunction of a 2D tungsten diselenide (WSe 2 ) layer is achieved by independently controlling two split-gate electrodes made of a ferroelectric 2D copper indium thiophosphate (CuInP 2 S 6 ) layer. Controlling the state encoded in the program gate enables switching between p, n, and ambipolar FeFET operating modes. The transistors exhibit on−off ratios exceeding 10 6 and hysteresis windows of up to 10 V width. The homojunction can change from Ohmic-like to diode behavior with a large rectification ratio of 10 4 . When programmed in the diode mode, the large built-in p−n junction electric field enables efficient separation of photogenerated carriers, making the device attractive for energy-harvesting applications. The implementation of the Re-FeFET for reconfigurable logic functions shows how a circuit can be reconfigured to emulate either polymorphic ferroelectric NAND/AND logic-in-memory or electronic XNOR logic with a long retention time exceeding 10 4 s. We also illustrate how a circuit design made of just two Re-FeFETs exhibits high logic expressivity with reconfigurability at runtime to implement several key nonvolatile 2-input logic functions. Moreover, the Re-FeFET circuit demonstrates high compactness, with an up to 80% reduction in transistor count compared to standard CMOS design. The 2D van de Waals Re-FeFET devices therefore exhibit promising potential for both More-than-Moore and beyond-Moore future of electronics, in particular for an energy-efficient implementation of in-memory computing and machine learning hardware, due to their multifunctionality and design compactness.

J-MISFET Hybrid Dual-Gate Switching Device for Multifunctional Optoelectronic Logic Gate Applications

“…To implement two-input logic gates such as NAND and NOR, it is necessary to construct the series- and the parallel-circuit systems, each comprising at least two driver transistors, to realize AND and OR switching behaviors. Recently, attempts to achieve AND and OR switching functions have been reported in advanced studies by utilizing split-gated − or multigated − FETs. In these approaches, there are crucial limitations of the fixed circuit designs and the usage of additional input lines for the target multi-input logic functions.…”

Applying the Wake-Up-like Effect to Enhance the Capabilities of Two-Dimensional Ferroelectric Field-Effect Transistors

“…To demonstrate the improved performance of our device following the wake-up-like effect, Table compares the key characteristics of various 2D FeFETs in the literature that utilize different ferroelectric materials as the gate dielectric and diverse semiconducting channels. Notably, WSe 2 is a bipolar 2D semiconductor and is sensitive to various external factors. Meanwhile, the ferroelectric polarization field in CIPS, induced by the short-range movement of Cu ions, is also particularly susceptible to the depolarization field in the heterostructure interface .…”

“…These results highlight the potential of our work to advance the performance of 2D FeFET devices and open up new opportunities in relevant fields. Our research presents a new paradigm for enhancing the capabilities of 2D FeFETs, which is expected to pave the way for future advancements in reconfigurable electronics27,42 and in-memory computing 43. The Supporting Information is available free of charge at https://pubs.acs.org/doi/10.1021/acsami.4c06177.…”

Single Wavelength Operating Neuromorphic Device Based on a Graphene–Ferroelectric Transistor

“…In particular, the high sensitivity of graphene resistance to the presence of nearby electric charges makes graphene hybrid structures of great interest . The powerful way to modulate charge environment is to use ferroelectric (FE) materials offering a large doping level modification and even polarity sign change, yet with the nonvolatile option to imprint multiple memory states. , Such structures can function with resistive readout of the ferroelectrically induced state, making device operation comparable with the resistive random access memories (RRAMs, memristors) . In electrically gated FE devices, graphene conductivity can be modified by several hundred of percents largely magnifying even tiny changes in charge environment.…”