An Ultra-Dense 2FeFET TCAM Design Based on a Multi-Domain FeFET Model

• Published in: IEEE transactions on circuits and systems. II, Express briefs Express briefs, 2019-09, Vol.66 (9), p.1577-1581
• Main Authors: Yin, Xunzhao, Ni, Kai, Reis, Dayane, Datta, Suman, Niemier, Michael, Hu, Xiaobo Sharon
• Format: Article
• Language: English
• Subjects: Associative memory; CMOS; content addressable storage; Delay; Delays; ferroelectric device; Ferroelectric materials; Ferroelectricity; Field effect transistors; Hysteresis; Iron; Logic gates; Machine learning; Nonvolatile memory; Random access memory; Resistance; Routers; Semiconductor device modeling; Semiconductor devices; Transistors
• ISSN: 1549-7747; 1558-3791
• DOI: 10.1109/TCSII.2018.2889225

Ternary content addressable memories (TCAMs) represent a form of logic-in-memory and are currently widely used in routers, caches, and efficient machine learning models. From a technology prospective, researchers have begun to consider various non-volatile (NV) memory technologies to design NV TCAMs that may offer improvements with respect to figures of merit, such as energy and delay when compared to conventional CMOS designs. Among these devices, ferroelectric field effect transistors (FeFETs) stand out due to their high ION/IOFF ratio, efficient voltage-driven write mechanism, low-cost, and CMOS-compatible fabrication process. We propose a 2FeFET TCAM design based on a state-of-the-art, experimentally calibrated FeFET model. We evaluate and compare our design with other TCAMs at the cell and array levels. Our results suggest that a 2FeFET TCAM requires 3.5×/3200× less write energy than CMOS/resistive random access memory (ReRAM) TCAMs, respectively. The cell area is 13% of that of a CMOS TCAM, and is on par with ReRAM designs. The search energy-delay-product of a 2FeFET TCAM is also 4.1×/2.8× less than CMOS/ReRAM TCAMs, respectively.