First Demonstration of BEOL-Compatible Ferroelectric TCAM Featuring a-IGZO Fe-TFTs with Large Memory Window of 2.9 V, Scaled Channel Length of 40 nm, and High Endurance of 10 8 Cycles
Chen Sun, Kaizhen Han, Subhranu Samanta, Qiwen Kong, Jishen Zhang, Haiwen Xu, Xinke Wang, Annie Kumar, Chengkuan Wang, Zijie Zheng, Xunzhao Yin, Kai Ni, Xiao Gong
Abstract
For the first time, we report BEOL-compatible ferroelectric ternary content-addressable memory (TCAM) based on amorphous IGZO (a-IGZO) channel and HfZrO 2 (HZO) ferroelectric (Fe) layer, achieving a much larger sensing margin as compared with other TCAM technologies. Our a-IGZO ferroelectric thin-film transistors (Fe-TFTs) were realized using a low-temperature process of 400 °C and an MFMIS structure with the flexibility to engineer the area ratio of the ferroelectric layer (A Fe ) and the metal-oxide-semiconductor layer (A MOS ). The Fe-TFTs not only enjoy the largest memory window (MW) of 2.9 V for HZO-based Fe-TFTs with oxide semiconductor channels and high endurance of 108 cycles, but also a high conductance ratio and small cycle-to-cycle variation, leading to a high recognition accuracy (90.4%) of handwritten digits. Ultra-scaled devices with a channel length L CH of 40 nm exhibit enhanced drive current with MW as large as 2.8 V.