First Demonstration of AFeFET-Based Capacitor-Less eDRAM Computing-in-Memory Featuring 4.84 Mb/mm2High Memory Density, 105s Long Retention Time, and >1010High Endurance

This paper, for the first time, reports the Anti-Ferroelectric FET (AFeFET)-based capacitor-less eDRAM Computing-in-Memory (CiM) with high memory density, long retention time, and high robustness and accuracy. The highlights include: (i) First fabricated AFeFET-based CiM cell, i.e., 1T1AF eDRAM cell, with Amorphous- Indium-Gallium-Zinc-Oxide (a-IGZO) channel length (LCH) of 25 nm; (ii) Proposed Almost-Refresh-Free (ARF) operation using the positive hysteresis window of AFeFETs with much longer retention time than conventional refresh operation; (iii) Proposed custom cluster design with locally shared computing units, achieving high memory density, reduced variation impact, and further high accuracy; (iv) High measured endurance over 1010 cycles for AFeFETs. Measurements and evaluation results show that the proposed 1T1AF eDRAM CiM achieves a record-high memory density of 4.84 Mb/mm2, ultra-long retention time of 105 s, a high compute density of 6.35 TOPS/mm2, and a high Cifar-10 accuracy of 91.9%, showing great potential for dense and robust eDRAM CiM designs.