Ultrafast Ternary Content-Addressable Nonvolatile Floating-Gate Memory Based on van der Waals Heterostructures

As a typical in-memory computing hardware design, nonvolatile ternary content-addressable memories (TCAMs) enable the logic operation and data storage for high throughout in parallel big data processing. However, TCAM cells based on conventional silicon-based devices suffer from structural complexity and large footprint limitations. Here, we demonstrate an ultrafast nonvolatile TCAM cell based on the MoTe₂/hBN/multilayer graphene (MLG) van der Waals heterostructure using a top-gated partial floating-gate field-effect transistor (PFGFET) architecture. Based on its ambipolar transport properties, the carrier type in the source/drain and central channel regions of the MoTe₂ channel can be efficiently tuned by the control gate and top gate, respectively, enabling the reconfigurable operation of the device in either memory or FET mode. When working in the memory mode, it achieves an ultrafast 60 ns programming/erase speed with a current on-off ratio of ∼10⁵, excellent retention capability, and robust endurance. When serving as a reconfigurable transistor, unipolar p-type and n-type FETs are obtained by adopting ultrafast 60 ns control-gate voltage pulses with different polarities. The monolithic integration of memory and logic within a single device enables the content-addressable memory (CAM) functionality. Finally, by integrating two PFGFETs in parallel, a TCAM cell with a high current ratio of ∼10⁵ between the match and mismatch states is achieved without requiring additional peripheral circuitry. These results provide a promising route for the design of high-performance TCAM devices for future in-memory computing applications.