1
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Park SO, Hong S, Sung SJ, Kim D, Seo S, Jeong H, Park T, Cho WJ, Kim J, Choi S. Phase-change memory via a phase-changeable self-confined nano-filament. Nature 2024; 628:293-298. [PMID: 38570686 DOI: 10.1038/s41586-024-07230-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 02/23/2024] [Indexed: 04/05/2024]
Abstract
Phase-change memory (PCM) has been considered a promising candidate for solving von Neumann bottlenecks owing to its low latency, non-volatile memory property and high integration density1,2. However, PCMs usually require a large current for the reset process by melting the phase-change material into an amorphous phase, which deteriorates the energy efficiency2-5. Various studies have been conducted to reduce the operation current by minimizing the device dimensions, but this increases the fabrication cost while the reduction of the reset current is limited6,7. Here we show a device for reducing the reset current of a PCM by forming a phase-changeable SiTex nano-filament. Without sacrificing the fabrication cost, the developed nano-filament PCM achieves an ultra-low reset current (approximately 10 μA), which is about one to two orders of magnitude smaller than that of highly scaled conventional PCMs. The device maintains favourable memory characteristics such as a large on/off ratio, fast speed, small variations and multilevel memory properties. Our finding is an important step towards developing novel computing paradigms for neuromorphic computing systems, edge processors, in-memory computing systems and even for conventional memory applications.
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Affiliation(s)
- See-On Park
- The School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Seokman Hong
- The School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Su-Jin Sung
- The School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Dawon Kim
- The School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Seokho Seo
- The School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Hakcheon Jeong
- The School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Taehoon Park
- The School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Won Joon Cho
- Device Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd., Suwon, Republic of Korea
| | - Jeehwan Kim
- Device Research Center, Samsung Advanced Institute of Technology (SAIT), Samsung Electronics Co., Ltd., Suwon, Republic of Korea
- Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, MA, USA
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
| | - Shinhyun Choi
- The School of Electrical Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
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2
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Abstract
We introduce a high-performance and ultra-steep slope switch, referred to as strain effect transistor (SET), with a subthreshold swing < 0.68 mV/decade at room temperature for 7 orders of magnitude change in the source-to-drain current based on atomically thin 1T'-MoTe2 as the channel material, piezoelectric lead zirconate titanate (PZT) as the gate dielectric, and nickel (Ni) as the source/drain contact metal. We exploit gate-voltage induced strain transduction in PZT leading to abrupt and reversible cracking of the metal contacts to achieve the abrupt switching. The SET also exhibits a low OFF-state current < 1 pA/μm, a high ON-state current > 1.8 mA/μm at a supply voltage of 1 V, a large current ON/OFF ratio > 1 × 109, and a high transconductance of > 100 μS/μm. The switching delay for the SET was found to be < 5 μs, and no device failure was observed even after 1 million (1 × 106) switching cycles.
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Affiliation(s)
- Sarbashis Das
- Electrical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Saptarshi Das
- Electrical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Engineering Science and Mechanics, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Material Research Institute, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Materials Science and Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
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3
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Aggarwal S, Milne T, Farmakidis N, Feldmann J, Li X, Shu Y, Cheng Z, Salinga M, Pernice WHP, Bhaskaran H. Antimony as a Programmable Element in Integrated Nanophotonics. NANO LETTERS 2022; 22:3532-3538. [PMID: 35451845 PMCID: PMC9101065 DOI: 10.1021/acs.nanolett.1c04286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/06/2021] [Revised: 04/01/2022] [Indexed: 06/14/2023]
Abstract
The use of nonlinear elements with memory as photonic computing components has seen a huge surge in interest in recent years with the rise of artificial intelligence and machine learning. A key component is the nonlinear element itself. A class of materials known as phase change materials has been extensively used to demonstrate the viability of such computing. However, such materials continue to have relatively slow switching speeds, and issues with cyclability related to phase segregation of phase change alloys. Here, using antimony (Sb) thin films with thicknesses less than 5 nm we demonstrate reversible, ultrafast switching on an integrated photonic platform with retention time of tens of seconds. We use subpicosecond pulses, the shortest used to switch such elements, to program seven distinct memory levels. This portends their use in ultrafast nanophotonic applications ranging from nanophotonic beam steerers to nanoscale integrated elements for photonic computing.
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Affiliation(s)
- Samarth Aggarwal
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, U.K.
| | - Tara Milne
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, U.K.
| | - Nikolaos Farmakidis
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, U.K.
| | - Johannes Feldmann
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, U.K.
| | - Xuan Li
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, U.K.
| | - Yu Shu
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, U.K.
| | - Zengguang Cheng
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, U.K.
- State
Key Laboratory of ASIC and System, School of Microelectronics, Fudan University, Shanghai 200433, China
| | - Martin Salinga
- Institut
für Materialphysik, Westfälische
Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149, Münster, Germany
| | - Wolfram HP Pernice
- Kirchhoff-Institute
for Physics, Heidelberg University, 69120 Heidelberg, Germany
| | - Harish Bhaskaran
- Department
of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, U.K.
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4
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Poddar S, Zhang Y, Gu L, Zhang D, Zhang Q, Yan S, Kam M, Zhang S, Song Z, Hu W, Liao L, Fan Z. Down-Scalable and Ultra-fast Memristors with Ultra-high Density Three-Dimensional Arrays of Perovskite Quantum Wires. NANO LETTERS 2021; 21:5036-5044. [PMID: 34124910 DOI: 10.1021/acs.nanolett.1c00834] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
With strikingly high speed, data retention ability and storage density, resistive RAMs have emerged as a forerunning nonvolatile memory. Here we developed a Re-RAM with ultra-high density array of monocrystalline perovskite quantum wires (QWs) as the switching matrix with a metallic silver conducting pathway. The devices demonstrated high ON/OFF ratio of ∼107 and ultra-fast switching speed of ∼100 ps which is among the fastest in literature. The devices also possess long retention time of over 2 years and record high endurance of ∼6 × 106 cycles for all perovskite Re-RAMs reported. As a concept proof, we have also successfully demonstrated a flexible Re-RAM crossbar array device with a metal-semiconductor-insulator-metal design for sneaky path mitigation, which can store information with long retention. Aggressive downscaling to ∼14 nm lateral dimension produced an ultra-small cell effectively having 76.5 nm2 area for single bit storage. Furthermore, the devices also exhibited unique optical programmability among the low resistance states.
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Affiliation(s)
- Swapnadeep Poddar
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Yuting Zhang
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Leilei Gu
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Daquan Zhang
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Qianpeng Zhang
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Shuai Yan
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Matthew Kam
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
| | - Sifan Zhang
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Zhitang Song
- State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China
| | - Weida Hu
- State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200000, China
| | - Lei Liao
- Key Laboratory for Micro/Nano Optoelectronic Devices of Ministry of Education & Hunan Provincial Key Laboratory of Low-Dimensional Structural Physics and Devices, School of Physics and Electronics, Hunan University, Changsha 410082, China
| | - Zhiyong Fan
- Department of Electronic & Computer Engineering, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR, China
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5
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Saxena N, Raghunathan R, Manivannan A. A scheme for enabling the ultimate speed of threshold switching in phase change memory devices. Sci Rep 2021; 11:6111. [PMID: 33731824 PMCID: PMC7969762 DOI: 10.1038/s41598-021-85690-9] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 03/04/2021] [Indexed: 11/09/2022] Open
Abstract
Phase change materials exhibit threshold switching (TS) that establishes electrical conduction through amorphous material followed by Joule heating leading to its crystallization (set). However, achieving picosecond TS is one of the key challenges for realizing non-volatile memory operations closer to the speed of computing. Here, we present a trajectory map for enabling picosecond TS on the basis of exhaustive experimental results of voltage-dependent transient characteristics of Ge2Sb2Te5 phase-change memory (PCM) devices. We demonstrate strikingly faster switching, revealing an extraordinarily low delay time of less than 50 ps for an over-voltage equal to twice the threshold voltage. Moreover, a constant device current during the delay time validates the electronic nature of TS. This trajectory map will be useful for designing PCM device with SRAM-like speed.
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Affiliation(s)
- Nishant Saxena
- Phase Change Memory Lab, Advanced Memory and Computing Group, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Rajamani Raghunathan
- UGC-DAE Consortium for Scientific Research, DAVV Campus, Khandwa Road, Indore, Madhya Pradesh, 452001, India
| | - Anbarasu Manivannan
- Phase Change Memory Lab, Advanced Memory and Computing Group, Department of Electrical Engineering, Indian Institute of Technology Madras, Chennai, 600036, India.
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6
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Exploring ultrafast threshold switching in In 3SbTe 2 phase change memory devices. Sci Rep 2019; 9:19251. [PMID: 31848416 PMCID: PMC6917803 DOI: 10.1038/s41598-019-55874-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Accepted: 11/21/2019] [Indexed: 11/09/2022] Open
Abstract
Phase change memory (PCM) offers remarkable features such as high-speed and non-volatility for universal memory. Yet, simultaneously achieving better thermal stability and fast switching remains a key challenge. Thus, exploring novel materials with improved characteristics is of utmost importance. We report here, a unique property-portfolio of high thermal stability and picosecond threshold switching characteristics in In3SbTe2 (IST) PCM devices. Our experimental findings reveal an improved thermal stability of amorphous IST compared to most other phase change materials. Furthermore, voltage dependent threshold switching and current-voltage characteristics corroborate an extremely fast, yet low electric field threshold switching operation within an exceptionally small delay time of less than 50 picoseconds. The combination of low electric field and high speed switching with improved thermal stability of IST makes the material attractive for next-generation high-speed, non-volatile memory applications.
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7
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Anam MK, Ahn EC. Understanding the effect of dry etching on nanoscale phase-change memory. NANOTECHNOLOGY 2019; 30:495202. [PMID: 31476740 DOI: 10.1088/1361-6528/ab4079] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
PCM (phase-change memory) is an important class of data storage, operating based on the Joule heating-induced reversible switching of chalcogenide alloys. Nanoscale PCM often requires advanced microfabrication techniques such as dry (plasma) etching, but the possible impacts of process damages or imperfections on the device performance still remain relatively unexplored. This is critical because some chemical etching species are known to cause over-etching with rough edge onto the sidewall of a phase-change material. It is also possible that the phase-change material experiences a composition change due to etching-induced re-deposition of by-products or thermal stress. In this study, a finite-element simulation is performed to understand the effect of dry etching on the RESET characteristics of a nanoscale PCM device to provide a guideline on the PCM manufacturing and cell design.
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Affiliation(s)
- Md Khirul Anam
- The Department of Electrical and Computer Engineering, The University of Texas at San Antonio, One UTSA Circle, San Antonio, Texas 78249, United States of America
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8
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Arjunan MS, Mondal A, Das A, Adarsh KV, Manivannan A. Multilevel accumulative switching processes in growth-dominated AgInSbTe phase change material. OPTICS LETTERS 2019; 44:3134-3137. [PMID: 31199399 DOI: 10.1364/ol.44.003134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 05/17/2019] [Indexed: 06/09/2023]
Abstract
Highly reproducible and precisely controlled gradual variation in optical reflectivity or electrical resistance between amorphous and crystalline phases of phase change (PC) material is a key requirement for multilevel programming. Here we report high-contrast multilevel set and reset operations through accumulative switching in growth-dominated AgInSbTe PC material using a nanosecond laser-based pump-probe technique. The precise tuning of fractions of crystallized or re-amorphized region is achieved by means of controlling the number of irradiated laser pulses enabling six stable multilevels with high-reflectivity contrast of 2% between any two states. Furthermore, Raman spectra of irradiated spots validate the structural changes involved during multilevel switching between amorphous and crystalline phases.
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9
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Díaz-Méndez R, Pupillo G, Mezzacapo F, Wallin M, Lidmar J, Babaev E. Phase-change switching in 2D via soft interactions. SOFT MATTER 2019; 15:355-358. [PMID: 30556570 DOI: 10.1039/c8sm01738g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
We present a new type of phase-change behavior relevant for information storage applications, that can be observed in 2D systems with cluster-forming ability. The temperature-based control of the ordering in 2D particle systems depends on the existence of a crystal-to-glass transition. We perform molecular dynamics simulations of models with soft interactions, demonstrating that the crystalline and amorphous structures can be easily tuned by heat pulses. The physical mechanism responsible for this behavior is a self-assembled polydispersity, that depends on the cluster-forming ability of the interactions. Therefore, the range of real materials that can perform such a transition is very wide in nature, ranging from colloidal suspensions to vortex matter. The state of the art in soft matter experimental setups, controlling interactions, polydispersity and dimensionality, makes it a very fertile ground for practical applications.
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Affiliation(s)
- Rogelio Díaz-Méndez
- Department of Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
| | - Guido Pupillo
- icFRC, ISIS (UMR 7006), IPCMS (UMR 7504), Université de Strasbourg and CNRS, 67000 Strasbourg, France
| | - Fabio Mezzacapo
- Laboratoire de Physique, CNRS UMR 5672, ENS de Lyon, F-69364 Lyon Cedex 07, France
| | - Mats Wallin
- Department of Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
| | - Jack Lidmar
- Department of Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
| | - Egor Babaev
- Department of Physics, KTH Royal Institute of Technology, SE-106 91 Stockholm, Sweden.
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10
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Shukla KD, Saxena N, Manivannan A. An ultrafast programmable electrical tester for enabling time-resolved, sub-nanosecond switching dynamics and programming of nanoscale memory devices. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2017; 88:123906. [PMID: 29289189 DOI: 10.1063/1.4999522] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Recent advancements in commercialization of high-speed non-volatile electronic memories including phase change memory (PCM) have shown potential not only for advanced data storage but also for novel computing concepts. However, an in-depth understanding on ultrafast electrical switching dynamics is a key challenge for defining the ultimate speed of nanoscale memory devices that demands for an unconventional electrical setup, specifically capable of handling extremely fast electrical pulses. In the present work, an ultrafast programmable electrical tester (PET) setup has been developed exceptionally for unravelling time-resolved electrical switching dynamics and programming characteristics of nanoscale memory devices at the picosecond (ps) time scale. This setup consists of novel high-frequency contact-boards carefully designed to capture extremely fast switching transient characteristics within 200 ± 25 ps using time-resolved current-voltage measurements. All the instruments in the system are synchronized using LabVIEW, which helps to achieve various programming characteristics such as voltage-dependent transient parameters, read/write operations, and endurance test of memory devices systematically using short voltage pulses having pulse parameters varied from 1 ns rise/fall time and 1.5 ns pulse width (full width half maximum). Furthermore, the setup has successfully demonstrated strikingly one order faster switching characteristics of Ag5In5Sb60Te30 (AIST) PCM devices within 250 ps. Hence, this novel electrical setup would be immensely helpful for realizing the ultimate speed limits of various high-speed memory technologies for future computing.
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Affiliation(s)
- Krishna Dayal Shukla
- Discipline of Electrical Engineering, Indian Institute of Technology Indore, Indore 453552, India
| | - Nishant Saxena
- Discipline of Electrical Engineering, Indian Institute of Technology Indore, Indore 453552, India
| | - Anbarasu Manivannan
- Discipline of Electrical Engineering, Indian Institute of Technology Indore, Indore 453552, India
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