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. An HfO2‐based reversible single‐domain ferroelectric (RSFE) film is developed by coupling the flexoelectric and surface effects to stabilize the NC effect. Moreover, the negative capacitance‐flash (NC‐flash) device is demonstrated by integrating a blocking layer composed of RSFE/dielectric heterostructure where the NC effect is stabilized. Furthermore, an AND flash‐like array and source‐follower/charge‐sharing vector‐matrix multiplication‐operation is applied to the NC‐flash for in‐memory computing.