Browsing by Author "Lee, Heng-Yuan"

Now showing 1 - 12 of 12

A 3T1R Nonvolatile TCAM Using MLC ReRAM with Sub-1ns Search Time
(2015-01-01)
Chang, Meng-Fan
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Lin, Chien-Chen
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Lee, Albert
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Kuo, Chia-Chen
;
Yang, Geng-Hau
A Comprehensive Modeling Framework for Ferroelectric Tunnel Junctions
(2019-01-01)
Huang, Hsin-Hui
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Wu, Tzu-Yun
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Chu, Yueh-Hua
;
Wu, Ming-Hung
;
Hsu, Chien-Hua
A modeling framework for ferroelectric tunnel junctions (FTJs) that considers nonpolar interfacial layers (ILs), multi-domain polarization, and complete ferroelectric/capacitive/tunneling currents simultaneously is proposed. This model explains both read and write operations including the controversial switching polarities of FTJ. We also provide useful guidelines for optimizing FTJ performance where the location of IL and the effective thickness ratio between ferroelectric and interfacial layers are found to be most critical.
Effect of ITO electrode with different oxygen contents on the electrical characteristics of HfOx RRAM devices
(2013-09-01)
Zhong, Chia-Wen
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Tzeng, Wen-Hsien
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Liu, Kou-Chen
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Lin, Horng-Chih
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Chang, Kow-Ming
In this study, the influence of indium tin oxide (ITO) top electrodes with different oxygen contents on the resistive switching characteristics of HfOx/TiN capacitor structure is investigated. Switching parameters, including set and reset voltage values, and high and low resistance values are highly related to the properties of ITO thin films. Higher resistance values in both states can be obtained when ITO thin films with higher oxygen contents are used as top electrodes; such values are accompanied by larger set voltages and fluctuating transient currents during the reset process. Based on the proposed filament model, we suggest that the switching mechanism of HfOx/TiN structure is attributed to the formation and rupture of conducting filamentary paths near the anodic side, which is highly correlated with the properties of the top electrode. The top electrode must be well determined to obtain reliable switching properties. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.
Extremely Compact Integrate-and-Fire STT-MRAM Neuron: A Pathway toward All-Spin Artificial Deep Neural Network
(2019-01-01)
Wu, Ming-Hung
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Hong, Ming-Chun
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Chang, Chih-Cheng
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Sahu, Paritosh
;
Wei, Jeng-Hua
This work reports the complete framework from device to architecture for deep learning acceleration in an all-spin artificial neural network (ANN) built by highly manufacturable STT-MRAM technology. The most compact analog integrate-and-fire neuron reported to date is developed based on the back-hopping oscillation in magnetic tunnel junctions. This novel device is unique because it performs numerous essential neural functions simultaneously, including current integration, voltage spike generation, state reset, and 4-bit precision. The device itself is also a stochastic binary synapse, and thus eases the implementation of the compact all-spin ANN with high accuracy for online training.
Forming-free HfO2 Bipolar RRAM Device with Improved Endurance and High Speed Operation
(2009)
Chen, Yu-Sheng
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Wu, Tai-Yuan
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Tzeng, Pei-Jer
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Chen, Pang-Shiu
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Lee, Heng-Yuan
Investigation of Radiation Hardness of HfO2 Resistive Random Access Memory
(2014-01-01)
Tsui, Bing-Yue
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Chang, Ko-Chin
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Shew, Bor-Yuan
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Lee, Heng-Yuan
;
Tsai, Ming-Jinn
Radiation hardness of HfO2-based resistive random-access memory (RRAM) is investigated using extreme ultra-violet (EUV) and X-ray as radiation source. The low-resistance state (LRS) is immune to irradiation, but temporary change of the high-resistance state (HRS) and endurance degradation could be observed at high total irradiation dose (TID). A physical model is proposed to explain these observations. It is concluded that the HfO2-based RRAM can be operated in high radiation environment, and EUV can be use to fabricate high-density RRAM array.
Investigation of the effect of different oxygen partial pressure to LaAlO3 thin film properties and resistive switching characteristics
(2011-12-01)
Liu, Kou-Chen
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Tzeng, Wen-Hsien
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Chang, Kow-Ming
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Huang, Jiun-Jie
;
Lee, Yun-Ju
The pulsed laser deposition and growth of a high-k dielectric lanthanum aluminate LaAlO3 (LAO) thin film on indium tin oxide/glass substrate at different oxygen partial pressure was studied. Based on the pulsed laser deposition growth mechanism, we explain how a difference in the oxygen partial pressure influences the surface roughness, formation of an interfacial layer, and the transparent resistive switching characteristics of LAO thin films. The micro-structure and oxygen concentration difference inside LAO thin films may be the main reason for the difference in electrical and resistive switching properties. Films grown at higher oxygen partial pressure displayed more reliable resistive switching performance, due to the formation of the interfacial layer and a lower concentration of oxygen vacancies. The interfacial layer serves as a good oxygen reservoir and the involvement of more oxygen ions ensures the switching reliability. The migration of oxygen ions between the interfacial layer and the LAO film under applied bias may be the switching mechanism. (C) 2011 Elsevier B. V. All rights reserved.
NV-BNN: An Accurate Deep Convolutional Neural Network Based on Binary STT-MRAM for Adaptive AI Edge
(2019-01-01)
Chang, Chih-Chcng
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Wu, Ming-Hung
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Lin, Jia-Wei
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Li, Chun-Hsien
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Parmar, Vivek
Binary STT-MRAM is a highly anticipated embedded non-volatile memory technology in advanced logic nodes <28 nm. How to enable its in-memory computing (IMC) capability is critical for enhancing AI Edge. Based on the soon-available STT-MRAM, we report the first binary deep convolutional neural network (NV-BNN) capable of both local and remote learning. Exploiting intrinsic cumulative switching probability, accurate online training of CIFAR-10 color images (similar to 90%) is realized using a relaxed endurance spec (switching <= 20 times) and hybrid digital/IMC design. For offline training, the accuracy loss due to imprecise weight placement can be mitigated using a rapid non-iterative training-with-noise and fine-tuning scheme.
Resistive switching characteristics of multilayered (HfO2/Al2O3)(n) n=19 thin film
(2012-02-01)
Tzeng, Wen-Hsien
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Zhong, Chia-Wen
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Liu, Kou-Chen
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Chang, Kow-Ming
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Lin, Horng-Chih
A transparent resistive random access memory used as Indium Tin Oxide (ITO) electrode, ITO/HfO2/Al2O3/center dot center dot center dot/HfO2/Al2O3/ITO capacitor structure is fabricated on glass substrate by atomic layer deposition. The unipolar resistive switching characteristics can be performed by applying the positive- or negative-bias through top electrode, however, the differences of switching and stability in the two different operations can be observed. The diversities of electrical property are attributed to different oxide/ITO interface materials, which influence the current flow of the injected electrons. Crown Copyright (c) 2011 Published by Elsevier B.V. All rights reserved.
Simulation-based study of negative-capacitance double-gate tunnel field-effect transistor with ferroelectric gate stack
(2016-04-01)
Liu, Chien
;
Chen, Ping-Guang
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Xie, Meng-Jie
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Liu, Shao-Nong
;
Lee, Jun-Wei
The concept of ferroelectric (FE) negative capacitance (NC) may be a turning point in overcoming the physical limitations imposed by the Boltzmann tyranny to realize next-generation state-of-the-art devices. Both the body factor (m-factor) and the transport mechanism (n-factor) are simultaneously improved by integrating an NC with a tunnel FET (TFET). The modeling approach is discussed in this study as well as the NC physics. By optimizing the thicknesses of FE, semiconductor, and interfacial layers, the capacitance of the FE layers is modulated to match that of a MOS resulting in the smallest subthreshold swing that is also hysteresis-free. An ultrathin-body double gate tunnel FET (UTB-DG-TFET) exhibits a steep slope (a subthreshold swing below 10 mV/dec over more than 4 orders of magnitude) for low-power applications (<0.2V switching voltage) to realize next-generation state-of-the-art devices. (C) 2016 The Japan Society of Applied Physics
Simulation-based study of negative-capacitance double-gate tunnel field-effect transistor with ferroelectric gate stack
(2016-04)
Liu, Chien
;
Chen, Ping-Guang
;
Xie, Meng-Jie
;
Liu, Shao-Nong
;
Lee, Jun-Wei
The concept of ferroelectric (FE) negative capacitance (NC) may be a turning point in overcoming the physical limitations imposed by the Boltzmann tyranny to realize next-generation state-of-the-art devices. Both the body factor (m-factor) and the transport mechanism (n-factor) are simultaneously improved by integrating an NC with a tunnel FET (TFET). The modeling approach is discussed in this study as well as the NC physics. By optimizing the thicknesses of FE, semiconductor, and interfacial layers, the capacitance of the FE layers is modulated to match that of a MOS resulting in the smallest subthreshold swing that is also hysteresis-free. An ultrathin-body double gate tunnel FET (UTB-DG-TFET) exhibits a steep slope (a subthreshold swing below 10 mV/dec over more than 4 orders of magnitude) for low-power applications (<0.2V switching voltage) to realize next-generation state-of-the-art devices. (C) 2016 The Japan Society of Applied Physics
Sub-nA Low-Current HZO Ferroelectric Tunnel Junction for High-Performance and Accurate Deep Learning Acceleration
(2019-01-01)
Wu, Tzu-Yun
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Huang, Hsin-Hui
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Chu, Yueh-Hua
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Chang, Chih-Cheng
;
Wu, Ming -Hung
This paper presents a unique opportunity of HZO ferroelectric tunnel junction (FTJ) for in-memory computing. The device operates at an extremely low sub-nA current while simultaneously achieving 50-ns fast switching, > 10(7) cycling endurance, > 10-yr retention, minimal variability, and analog state modulation. We analyze an FTJ-based deep binary neural network. It achieves better accuracy and remarkable 702, 101, and 7 x 10(4) times improvements in power, area, and energy area product efficiency compared with those using NVMs with a typical mu A cell current designed for fast memory access.