The Opportunity of Negative Capacitance Behavior in Flash Memory for High-Density and Energy-Efficient In-Memory Computing Applications

Flash memory is a promising candidate for use in in-memory computing (IMC) owing to its multistate operations, high on/off ratio, non-volatility, and the maturity of device technologies. However, its high operation voltage, slow operation speed, and string array structure severely degrade the energy efficiency of IMC. To address these challenges, a novel negative capacitance-flash (NC-flash) memory-based IMC architecture is proposed. To stabilize and utilize the negative capacitance (NC) effect, a HfO2-based reversible single-domain ferroelectric (RSFE) layer is developed by coupling the flexoelectric and surface effects, which generates a large internal field and surface polarization pinning. Furthermore, NC-flash memory is demonstrated for the first time by introducing a RSFE and dielectric heterostructure layer in which the NC effect is stabilized as a blocking layer. Consequently, an energy-efficient and high-throughput IMC is successfully demonstrated using an AND flash-like cell arrangement and source-follower/charge-sharing vector-matrix multiplication operation on a high-performance NC-flash memory.