Drain-Erase Scheme in Ferroelectric Field Effect Transistor - Part II: 3-D-NAND Architecture for In-Memory Computing

Ferroelectric-doped HfO₂-based ferroelectric field-effect transistors (FeFETs) are being actively explored as emerging nonvolatile memory (NVM) devices with the potential for in-memory computing. In this two-part article, we explore the feasibility of the FeFET-based 3-D NAND architecture for both in situ training and inference. To address the challenge of erase-by-block in a NAND-like structure, we propose and experimentally demonstrate the drain-erase scheme to enable the individual cell's program/erase/inhibition, which is necessary for individual weight updates in in situ training. We described the device characterization of different drain-erase conditions and results in Part I. The array-level design for this drain-erase scheme for both AND-type and NAND-type array is addressed in this Part II. A 3-D vertical channel FeFET array architecture is proposed to accelerate the vector-matrix multiplication (VMM). 3-D timing sequence of the weight update rule is designed and verified through the 3-D-array-level SPICE simulation. Finally, the VMM operation is simulated in a 3-D NAND-like FeFET array.