A novel high-speed, high-density and low-power memory design for data-intensive applications based on cross-point architecture (Advisor - Prof. Qianqian Huang; Mentor - Prof.Zhiyuan Fu)
Overview
Hafnia-based FE capacitor cross-point array structure and applications.
With the fast development of artificial intelligence and data-centric computing technology, date-intensive demands grow explosively, leading to a surge in research on highdensity, low-power, and high-speed memory technologies. Among various emerging non-volatile memories, hafnia-based ferroelectric (FE) memories have attracted tremendous attention in recent years due to the properties of fast polarization switching, low write energy, good scalability, and high CMOS-compatibility. Benefiting from such excellent properties, hafnia-based FE capacitor cross-point array has been utilized in the field of neuromorphic computing, in-memory sensor, and the main goal “high-performance and low-power memory applications” of this project, so called XP-FeRAM. Focusing on this target, device and circuit co-optimization of a novel hafnia-based XP-FeRAM are comprehensively investigated for high-density, high-speed and low-power memory applications. Planar and 3D vertical-stacked XPFeRAM designs are demonstrated with application-specific device optimization, and the outstanding comprehensive performance are achieved with high 2Pr, excellent disturbance immunity under low-voltage operation and fast switching at scaled size, as well as good device reliability. A modified V/2 operation scheme with in-situ write-back is further presented, leading to faster operation and lower power consumption than traditional 1T1C FeRAM. Combined with its excellent scalability, XP-FeRAM shows strong potential as a competitive candidate of future non-volatile memory technology for data-intensive demands.
Details
Results
XP-FeRAM array-level test platform and the write&read validation.
References
2024
IEDM 2024
Comprehensive Performance Re-Assessment of Hafnia-Based Cross-Point FeRAM with Ultra-Fast and Low-Power Operation from Device/Array Perspective
In this work, hafnia-based selector-less cross-point FeRAM (XP-FeRAM) with ultra-fast and low-power operation is experimentally demonstrated from device-level optimization to array-level evaluation for embedded and standalone memories. For device optimization, the impacts of ferroelectric (FE) layer deposition process sequence considering different applications are investigated for the first time with the awareness of switching speed. Optimized devices show the outstanding comprehensive performance with 1.5ns switching, 2Pr of 47μC/cm2 and excellent disturbance immunity under 1.6V low-voltage operation, alone with the good reliability of extrapolated 1014 endurance cycles and 10 years data retention in scaled devices. Moreover, from array perspective, a modified V/2 operation scheme with in-situ write-back is further proposed and experimentally demonstrated in the fabricated XP-FeRAM array, resulting in the even faster operation and lower power consumption than 1T1C FeRAM. Additionally, based on the established parasitic circuit model, memory performances and scalability design spaces are robustly evaluated, showing the great potential of XP-FeRAMs for high-speed, high-density and low-power memory applications.
@inproceedings{cao2024comprehensive,title={Comprehensive Performance Re-Assessment of Hafnia-Based Cross-Point FeRAM with Ultra-Fast and Low-Power Operation from Device/Array Perspective},author={Cao, Shengjie and Fu, Zhiyuan and Deng, Minyue and Zheng, Hao and Huang, Qianqian and Huang, Ru},booktitle={2024 IEEE International Electron Devices Meeting (IEDM)},pages={1--4},year={2024},organization={IEEE},doi={10.1109/IEDM50854.2024.10873447}}
IEEE TED 2024
Hafnia-Based High-Disturbance-Immune and Selector-Free Cross-Point FeRAM
This study presents an experimental demonstration of 3-D-stackable hafnia-based selector-free cross-point FeRAM, with enhanced disturbance immunity achieved through design technology co-optimization (DTCO). Considering ferroelectric (FE) dynamics, the disturbance behavior of FE devices has been systematically and quantitatively examined using the proposed “pulse-disturb” analysis method. Through the optimization of grain uniformity and interfacial layers, the fabricated Hf0.5Zr0.5O2 (HZO) FE capacitor exhibits large grain size exceeding 30 nm with record best disturbance immunity among FE-HZO. It also achieves a significant improvement of MW in selector-free FeRAM operation and enhanced remnant polarization ( Pr ) of approximately 23 μC/cm2, low operation voltage (2.4 V), high endurance (1013 cycles), long retention capability (ten years), and excellent potential for 3-D stacking. Moreover, to address the multiple pulses disturb issue, a novel “disturb-recovery” pulsing method is proposed, showing multidisturb-free operation for practical cross-point array applications. Based on the above strategies, 1-kbit selector-free cross-point FeRAM array is experimentally demonstrated with successful read/write operation, indicating its great potential for high-density and low-power memory applications.
@article{fu2024hafnia,title={Hafnia-Based High-Disturbance-Immune and Selector-Free Cross-Point FeRAM},author={Fu, Zhiyuan and Cao, Shengjie and Zheng, Hao and Luo, Jin and Huang, Qianqian and Huang, Ru},journal={IEEE Transactions on Electron Devices},year={2024},publisher={IEEE},doi={10.1109/TED.2024.3369569}}
2023
IEDM 2023
First demonstration of hafnia-based selector-free FeRAM with high disturb immunity through design technology co-optimization
In this work, 3D-stackable hafnia-based selector-free FeRAM is experimentally demonstrated for the first time, showing significantly improved disturb immunity through design technology co-optimization. With ferroelectric (FE) dynamics considered, based on the proposed pulse-disturb analysis method for FE capacitors, the disturb behavior of FE-based cross-point arrays has been systematically and quantitatively investigated. By grain uniformity and interfacial layer optimization, the fabricated optimized Hf0.5Zr0.5O2 (HZO) FE capacitor shows the record best disturb immunity among FE-HZO and 71.3% of MW improvement for FeRAM operation due to the large grain size (>30nm), along with the advantages of enhanced remnant polarization (Pr) ( 23 μC/cm2), low operation voltage (2.4V), high endurance (1013 cycles), long retention (10 years) and excellent 3D-stackable potential. Moreover, to address the multiple pulses disturb issue, a new disturb-recovery pulsing method is further proposed, showing multi-disturb-free operation for practical cross-point array applications. Based on the above strategies, the first 1 kbit cross-point array for selector-free FeRAM based on the optimized HZO devices is experimentally demonstrated with successful read/write operation, indicating its great potential for high-density and low-power memory applications.
@inproceedings{fu2023first,title={First demonstration of hafnia-based selector-free FeRAM with high disturb immunity through design technology co-optimization},author={Fu, Zhiyuan and Cao, Shengjie and Zheng, Hao and Luo, Jin and Huang, Qianqian and Huang, Ru},booktitle={2023 International Electron Devices Meeting (IEDM)},pages={1--4},year={2023},organization={IEEE},doi={10.1109/IEDM45741.2023.10413887}}
