A Multi-Bit CAM Design With Ultra-High Density and Energy Efficiency Based on FeFET NAND

We have proposed and experimentally demonstrated a novel multi-bit content addressable memory (CAM) cell based on two series connected ferroelectric FETs (FeFETs). Thanks to the multilevel cell (MLC) operations of FeFETs and complementary inputs of search lines (SLs), CAM functions with 2-bits/cell are realized. Bit density can be further boosted by implementing more stable states of FeFETs. In addition, the CAM cells can be integrated in a form of 3D vertical FeFET NAND, which enables ultra-high density and energy efficiency at low cost. A
$4\times $
4 FeFET NAND array is fabricated, and parallel search of a query with 4-bits data in a whole NAND block is experimentally demonstrated. The proposed CAM design is promising for future data-centric computing systems.