Gate‐Switchable BST Ferroelectric MoS₂ FETs for Non‐Volatile Digital Memory and Analog Memristor

Abstract

To overcome the von Neumann bottleneck between memory and computing, the novel architectures with computing in‐memory are paid much attention and expected to be compatible with digital logic computing and/or analog brain‐inspired neuromorphic computing. Herein, by combining the Ba0.6Sr0.4TiO3 (BST) ferroelectric film and MoS2 layered semiconductor, a non‐volatile memory is constructed, which deliver the gate‐switchable function between the digital and analog functionality modes. The on/off ratio, subthreshold swing, and carrier mobility of MoS2/BST ferroelectric field‐effect transistor (FeFET) are 4.95×106, 68 mV dec−1, and 16.7 cm2 V−1 s−1, respectively. By a small electrical stimulation, the device demonstrates remarkable non‐volatile memory properties, including robust long‐term retention of ≈3000 s, superior endurance over 34 000 cycles, low operating energy at ≈0.3 pJ per spike. By a large electrical stress, it exhibits well memristive behavior and gating history dependent accumulation/diminution effect, which is attributed to the charge dynamic trapping/de‐trapping activation at the MoS2/BST interface. Following the historic memory behaviors, a cryptosystem is developed with auto‐generated reading log which is tamper‐resistant at hardware level. Moreover, the synaptic functions are realized on the device such as the short‐term potentiation/depression and gating‐depending synaptic plasticity. This study shows the opportunities of multi‐functionalities integration in a single FeFET device.