The Experts below are selected from a list of 491307 Experts worldwide ranked by ideXlab platform
Songlin Feng - One of the best experts on this subject based on the ideXlab platform.
-
nitrogen doped sb rich si sb te Phase Change material for high performance Phase Change memory
Acta Materialia, 2013Co-Authors: Xilin Zhou, Kun Ren, Yan Cheng, Bo Liu, Songlin FengAbstract:The effects of nitrogen doping on the Phase-Change performance of Sb-rich Si–Sb–Te materials are systemically investigated, focusing on the chemical state and the role of nitrogen upon crystallization. The tendency of N atoms to bond with Si (SiNx) in the crystalline film is analyzed by X-ray photoelectron spectroscopy. The microstructures of the materials mixed with Sb2Te crystal grains and amorphous Si/SiNx regions are elucidated via in situ transmission electron microscopy, from which a percolation behavior is demonstrated to possibly describe the random crystallization feature in the nucleation-dominated nanocomposite material. The Phase-Change memory cells based on N-doped Sb-rich Si–Sb–Te materials display more stable and reliable electrical performance than the nitrogen-free ones. An endurance characteristic in the magnitude of 10 7 cycles of the Phase-Change memory cells is realized with moderate nitrogen addition,
-
advantages of sixsb2te Phase Change material and its applications in Phase Change random access memory
Scripta Materialia, 2011Co-Authors: Yan Cheng, Sannian Song, Bo Liu, Ting Zhang, Zhitang Song, X Liu, Songlin FengAbstract:Si-doped Sb 2 Te Phase-Change material was investigated for the application of Phase-Change memory. During the electrical test, Si 0.53 Sb 2 Te needs a lower Phase-Change operating voltage than Ge 2 Sb 2 Te 5 . For the storage of data for 10 years, Si 0.53 Sb 2 Te needs an annealing temperature that is about 24 °C higher than for Ge 2 Sb 2 Te 5 . Crystallization Changes from being growth dominated to being nucleation dominated. X-ray diffraction patterns indicate that the polycrystalline Si x Sb 2 Te series has a δ-Phase with a rhombohedral crystalline structure, similar to the pure Sb 2 Te.
-
Sb-rich Si–Sb–Te Phase-Change Material for Phase-Change Random Access Memory Applications
IEEE Transactions on Electron Devices, 2011Co-Authors: Liangcai Wu, Sannian Song, Xilin Zhou, Yan Cheng, Songlin FengAbstract:An Sb-rich (48 at.%) Si-Sb-Te Phase-Change material with moderate Si content (24 at.%) is proposed for Phase-Change random access memory (PCRAM) applications. The real time amorphous to crystalline transformation was studied by in situ transmission electron microscopy observations and in situ resistance measurements. The results of time-dependent resistance measurements show that the Si24Sb48Te28 Phase-Change material has data retention of 10 years at about 382 K, suggesting a more stable amorphous state than the usual Ge2Sb2Te5 (GST) Phase-Change material. The reversible set-reset ability of the PCRAM cell based on the Si24Sb48Te28 Phase-Change material is much better than that of the device employing GST. The programming cycles can reach 2.2 × 104 under a set pulse of 1.5 V/1000 ns with a 30-ns falling edge and a reset pulse of 3.5 V/400 ns, whereas the resistance contrast retains a value of as large as two orders of magnitude.
-
novel Phase Change material gesbse for application of three level Phase Change random access memory
Solid-state Electronics, 2010Co-Authors: Zhitang Song, Ting Zhang, Bo Liu, Songlin FengAbstract:Abstract Se-doped GeSb were investigated for the possible applications in three-level Phase-Change memory. Ge15Sb85Se0.8, as a typical composition, has two abrupt drops of electrical resistance during an in situ temperature-dependent resistance measurement. The large-resistance Change in the two drops and the stable middle-resistance state make Ge15Sb85Se0.8 a good candidate for the three-level data storage applications. Three-level Phase-Change memory based on Ge15Sb85Se0.8 has been fabricated and demonstrated. X-ray diffraction patterns indicate that the reason for the middle-resistance state in Ge15Sb85Se0.8 is due to the incomplete crystallization.
Matthias Wuttig - One of the best experts on this subject based on the ideXlab platform.
-
Aging mechanisms in amorphous Phase-Change materials
Nature Communications, 2015Co-Authors: J.-y. Raty, Jennifer Luckas, Riccardo Mazzarello, Christophe Bichara, Wei Zhang, Matthias WuttigAbstract:Aging is a ubiquitous phenomenon in glasses. In the case of Phase-Change materials, it leads to a drift in the electrical resistance, which hinders the development of ultrahigh density storage devices. Here we elucidate the aging process in amorphous GeTe, a prototypical Phase-Change material, by advanced numerical simulations, photothermal deflection spectroscopy and impedance spectroscopy experiments. We show that aging is accompanied by a progressive Change of the local chemical order towards the crystalline one. Yet, the glass evolves towards a covalent amorphous network with increasing Peierls distortion, whose structural and electronic properties drift away from those of the resonantly bonded crystal. This behaviour sets Phase-Change materials apart from conventional glass-forming systems, which display the same local structure and bonding in both Phases.
-
Phase Change materials and Phase Change memory
Mrs Bulletin, 2014Co-Authors: Simone Raoux, Matthias Wuttig, Feng Xiong, Eric PopAbstract:Phase Change memory (PCM) is an emerging technology that combines the unique properties of Phase Change materials with the potential for novel memory devices, which can help lead to new computer architectures. Phase Change materials store information in their amorphous and crystalline Phases, which can be reversibly switched by the application of an external voltage. This article describes the advantages and challenges of PCM. The physical properties of Phase Change materials that enable data storage are described, and our current knowledge of the Phase Change processes is summarized. Various designs of PCM devices with their respective advantages and integration challenges are presented. The scaling limits of PCM are addressed, and its performance is compared to competing existing and emerging memory technologies. Finally, potential new applications of Phase Change devices such as neuromorphic computing and Phase Change logic are outlined.
-
Disorder-induced localization in crystalline Phase-Change materials.
Nature materials, 2011Co-Authors: Theo Siegrist, Hessel Volker, Haaf Volker, Philippe Jost, Michael Woda, C. Schlockermann, P Merkelbach, Matthias WuttigAbstract:Localization of charge carriers in crystalline solids has been the subject of numerous investigations over more than half a century. Materials that show a metal-insulator transition without a structural Change are therefore of interest. Mechanisms leading to metal-insulator transition include electron correlation (Mott transition) or disorder (Anderson localization), but a clear distinction is difficult. Here we report on a metal-insulator transition on increasing annealing temperature for a group of crystalline Phase-Change materials, where the metal-insulator transition is due to strong disorder usually associated only with amorphous solids. With pronounced disorder but weak electron correlation, these Phase-Change materials form an unparalleled quantum state of matter. Their universal electronic behaviour seems to be at the origin of the remarkable reproducibility of the resistance switching that is crucial to their applications in non-volatile-memory devices. Controlling the degree of disorder in crystalline Phase-Change materials might enable multilevel resistance states in upcoming storage devices.
-
A map for Phase-Change materials.
Nature Materials, 2008Co-Authors: Dominic Lencer, Martin Salinga, Blazej Grabowski, Tilmann Hickel, Jörg Neugebauer, Matthias WuttigAbstract:Phase-Change materials are widely used as non-volatile memories, for example in optical data storage, but the search for improved Phase-Change materials has proved difficult. Based on a fundamental understanding of their bonding characteristics, a systematic prediction of Phase-Change properties has now become possible.
-
Resonant bonding in crystalline Phase-Change materials.
Nature materials, 2008Co-Authors: Kostiantyn Shportko, Dominic Lencer, Stephan Kremers, Michael Woda, John Robertson, Matthias WuttigAbstract:The identification of materials suitable for non-volatile Phase-Change memory applications is driven by the need to find materials with tailored properties for different technological applications and the desire to understand the scientific basis for their unique properties. Here, we report the observation of a distinctive and characteristic feature of Phase-Change materials. Measurements of the dielectric function in the energy range from 0.025 to 3 eV reveal that the optical dielectric constant is 70-200% larger for the crystalline than the amorphous Phases. This difference is attributed to a significant Change in bonding between the two Phases. The optical dielectric constant of the amorphous Phases is that expected of a covalent semiconductor, whereas that of the crystalline Phases is strongly enhanced by resonant bonding effects. The quantification of these is enabled by measurements of the electronic polarizability. As this bonding in the crystalline state is a unique fingerprint for Phase-Change materials, a simple scheme to identify and characterize potential Phase-Change materials emerges.
Xilin Zhou - One of the best experts on this subject based on the ideXlab platform.
-
wide bandgap Phase Change material tuned visible photonics
Advanced Functional Materials, 2019Co-Authors: Weiling Dong, Xilin Zhou, Hailong Liu, Jitendra K Behera, Kandammathe Valiyaveedu Sreekanth, Joel K W Yang, Robert E SimpsonAbstract:Light strongly interacts with structures that are of a similar scale to its wavelength; typically nanoscale features for light in the visible spectrum. However, the optical response of these nanostructures is usually fixed during the fabrication. Phase Change materials offer a way to tune the properties of these structures in nanoseconds. Until now, Phase Change active photonics use materials that strongly absorb visible light, which limits their application in the visible spectrum. In contrast, Stibnite (Sb2S3) is an under-explored Phase Change material with a band gap that can be tuned in the visible spectrum from 2.0 to 1.7 eV. We deliberately couple this tuneable band gap to an optical resonator such that it responds dramatically in the visible spectrum to Sb2S3 reversible structural Phase transitions. We show that this optical response can be triggered both optically and electrically. High speed reprogrammable Sb2S3 based photonic devices, such as those reported here, are likely to have wide applications in future intelligent photonic systems, holographic displays, and micro-spectrometers.
-
nitrogen doped sb rich si sb te Phase Change material for high performance Phase Change memory
Acta Materialia, 2013Co-Authors: Xilin Zhou, Kun Ren, Yan Cheng, Bo Liu, Songlin FengAbstract:The effects of nitrogen doping on the Phase-Change performance of Sb-rich Si–Sb–Te materials are systemically investigated, focusing on the chemical state and the role of nitrogen upon crystallization. The tendency of N atoms to bond with Si (SiNx) in the crystalline film is analyzed by X-ray photoelectron spectroscopy. The microstructures of the materials mixed with Sb2Te crystal grains and amorphous Si/SiNx regions are elucidated via in situ transmission electron microscopy, from which a percolation behavior is demonstrated to possibly describe the random crystallization feature in the nucleation-dominated nanocomposite material. The Phase-Change memory cells based on N-doped Sb-rich Si–Sb–Te materials display more stable and reliable electrical performance than the nitrogen-free ones. An endurance characteristic in the magnitude of 10 7 cycles of the Phase-Change memory cells is realized with moderate nitrogen addition,
-
Carbon-doped Ge2Sb2Te5 Phase Change material: A candidate for high-density Phase Change memory application
Applied Physics Letters, 2012Co-Authors: Xilin Zhou, Dongning Yao, Sannian Song, Liangcai Wu, Cheng Peng, Min Zhu, Bo LiuAbstract:Carbon-doped Ge2Sb2Te5 material is proposed for high-density Phase-Change memories. The carbon doping effects on electrical and structural properties of Ge2Sb2Te5 are studied by in situ resistance and x-ray diffraction measurements as well as optical spectroscopy. C atoms are found to significantly enhance the thermal stability of amorphous Ge2Sb2Te5 by increasing the degree of disorder of the amorphous Phase. The reversible electrical switching capability of the Phase-Change memory cells is improved in terms of power consumption with carbon addition. The endurance of ∼2.1 × 104 cycles suggests that C-doped Ge2Sb2Te5 film will be a potential Phase-Change material for high-density storage application.
-
al1 3sb3te material for Phase Change memory application
Applied Physics Letters, 2011Co-Authors: Cheng Peng, Dongning Yao, Xilin Zhou, Bo Liu, Hongjia Song, Pingxiong Yang, Junhao ChuAbstract:Comparing with Ge2Sb2Te5, Al1.3Sb3Te is proved to be a promising candidate for Phase-Change memory use because of its higher crystallization temperature (∼210 °C), larger crystallization activation energy (3.32 eV), and better data retention ability (124 °C for 10 yr). Furthermore, Al1.3Sb3Te shows fast Phase Change speed and crystallizes into a uniformly embedded crystal structure. As short as 10 ns width, voltage pulse can realize reversible operations for Al1.3Sb3Te based Phase-Change memory cell. Moreover, Phase-Change memory cell based on Al1.3Sb3Te material also has good endurance (∼2.5 × 104 cycles) and an enough resistance ratio of ∼102.
-
Sb-rich Si–Sb–Te Phase-Change Material for Phase-Change Random Access Memory Applications
IEEE Transactions on Electron Devices, 2011Co-Authors: Liangcai Wu, Sannian Song, Xilin Zhou, Yan Cheng, Songlin FengAbstract:An Sb-rich (48 at.%) Si-Sb-Te Phase-Change material with moderate Si content (24 at.%) is proposed for Phase-Change random access memory (PCRAM) applications. The real time amorphous to crystalline transformation was studied by in situ transmission electron microscopy observations and in situ resistance measurements. The results of time-dependent resistance measurements show that the Si24Sb48Te28 Phase-Change material has data retention of 10 years at about 382 K, suggesting a more stable amorphous state than the usual Ge2Sb2Te5 (GST) Phase-Change material. The reversible set-reset ability of the PCRAM cell based on the Si24Sb48Te28 Phase-Change material is much better than that of the device employing GST. The programming cycles can reach 2.2 × 104 under a set pulse of 1.5 V/1000 ns with a 30-ns falling edge and a reset pulse of 3.5 V/400 ns, whereas the resistance contrast retains a value of as large as two orders of magnitude.
Bo Liu - One of the best experts on this subject based on the ideXlab platform.
-
nitrogen doped sb rich si sb te Phase Change material for high performance Phase Change memory
Acta Materialia, 2013Co-Authors: Xilin Zhou, Kun Ren, Yan Cheng, Bo Liu, Songlin FengAbstract:The effects of nitrogen doping on the Phase-Change performance of Sb-rich Si–Sb–Te materials are systemically investigated, focusing on the chemical state and the role of nitrogen upon crystallization. The tendency of N atoms to bond with Si (SiNx) in the crystalline film is analyzed by X-ray photoelectron spectroscopy. The microstructures of the materials mixed with Sb2Te crystal grains and amorphous Si/SiNx regions are elucidated via in situ transmission electron microscopy, from which a percolation behavior is demonstrated to possibly describe the random crystallization feature in the nucleation-dominated nanocomposite material. The Phase-Change memory cells based on N-doped Sb-rich Si–Sb–Te materials display more stable and reliable electrical performance than the nitrogen-free ones. An endurance characteristic in the magnitude of 10 7 cycles of the Phase-Change memory cells is realized with moderate nitrogen addition,
-
Carbon-doped Ge2Sb2Te5 Phase Change material: A candidate for high-density Phase Change memory application
Applied Physics Letters, 2012Co-Authors: Xilin Zhou, Dongning Yao, Sannian Song, Liangcai Wu, Cheng Peng, Min Zhu, Bo LiuAbstract:Carbon-doped Ge2Sb2Te5 material is proposed for high-density Phase-Change memories. The carbon doping effects on electrical and structural properties of Ge2Sb2Te5 are studied by in situ resistance and x-ray diffraction measurements as well as optical spectroscopy. C atoms are found to significantly enhance the thermal stability of amorphous Ge2Sb2Te5 by increasing the degree of disorder of the amorphous Phase. The reversible electrical switching capability of the Phase-Change memory cells is improved in terms of power consumption with carbon addition. The endurance of ∼2.1 × 104 cycles suggests that C-doped Ge2Sb2Te5 film will be a potential Phase-Change material for high-density storage application.
-
advantages of sixsb2te Phase Change material and its applications in Phase Change random access memory
Scripta Materialia, 2011Co-Authors: Yan Cheng, Sannian Song, Bo Liu, Ting Zhang, Zhitang Song, X Liu, Songlin FengAbstract:Si-doped Sb 2 Te Phase-Change material was investigated for the application of Phase-Change memory. During the electrical test, Si 0.53 Sb 2 Te needs a lower Phase-Change operating voltage than Ge 2 Sb 2 Te 5 . For the storage of data for 10 years, Si 0.53 Sb 2 Te needs an annealing temperature that is about 24 °C higher than for Ge 2 Sb 2 Te 5 . Crystallization Changes from being growth dominated to being nucleation dominated. X-ray diffraction patterns indicate that the polycrystalline Si x Sb 2 Te series has a δ-Phase with a rhombohedral crystalline structure, similar to the pure Sb 2 Te.
-
al1 3sb3te material for Phase Change memory application
Applied Physics Letters, 2011Co-Authors: Cheng Peng, Dongning Yao, Xilin Zhou, Bo Liu, Hongjia Song, Pingxiong Yang, Junhao ChuAbstract:Comparing with Ge2Sb2Te5, Al1.3Sb3Te is proved to be a promising candidate for Phase-Change memory use because of its higher crystallization temperature (∼210 °C), larger crystallization activation energy (3.32 eV), and better data retention ability (124 °C for 10 yr). Furthermore, Al1.3Sb3Te shows fast Phase Change speed and crystallizes into a uniformly embedded crystal structure. As short as 10 ns width, voltage pulse can realize reversible operations for Al1.3Sb3Te based Phase-Change memory cell. Moreover, Phase-Change memory cell based on Al1.3Sb3Te material also has good endurance (∼2.5 × 104 cycles) and an enough resistance ratio of ∼102.
-
novel Phase Change material gesbse for application of three level Phase Change random access memory
Solid-state Electronics, 2010Co-Authors: Zhitang Song, Ting Zhang, Bo Liu, Songlin FengAbstract:Abstract Se-doped GeSb were investigated for the possible applications in three-level Phase-Change memory. Ge15Sb85Se0.8, as a typical composition, has two abrupt drops of electrical resistance during an in situ temperature-dependent resistance measurement. The large-resistance Change in the two drops and the stable middle-resistance state make Ge15Sb85Se0.8 a good candidate for the three-level data storage applications. Three-level Phase-Change memory based on Ge15Sb85Se0.8 has been fabricated and demonstrated. X-ray diffraction patterns indicate that the reason for the middle-resistance state in Ge15Sb85Se0.8 is due to the incomplete crystallization.
Simone Raoux - One of the best experts on this subject based on the ideXlab platform.
-
Phase Change materials and Phase Change memory
Mrs Bulletin, 2014Co-Authors: Simone Raoux, Matthias Wuttig, Feng Xiong, Eric PopAbstract:Phase Change memory (PCM) is an emerging technology that combines the unique properties of Phase Change materials with the potential for novel memory devices, which can help lead to new computer architectures. Phase Change materials store information in their amorphous and crystalline Phases, which can be reversibly switched by the application of an external voltage. This article describes the advantages and challenges of PCM. The physical properties of Phase Change materials that enable data storage are described, and our current knowledge of the Phase Change processes is summarized. Various designs of PCM devices with their respective advantages and integration challenges are presented. The scaling limits of PCM are addressed, and its performance is compared to competing existing and emerging memory technologies. Finally, potential new applications of Phase Change devices such as neuromorphic computing and Phase Change logic are outlined.
-
Phase Change Memory
Proceedings of the IEEE, 2010Co-Authors: H.p. Wong, Jiale Liang, John P. Reifenberg, Bipin Rajendran, Simone Raoux, Mehdi Asheghi, H S P Wong, Sang Bum Kim, Kenneth E GoodsonAbstract:In this paper, recent progress of Phase Change memory (PCM) is reviewed. The electrical and thermal proper- ties of Phase Changematerials are surveyed with a focus on the scalability of the materials and their impact on device design. Innovations in the device structure, memory cell selector, and strategies for achieving multibit operation and 3-D, multilayer high-density memory arrays are described. The scaling prop- erties of PCM are illustrated with recent experimental results using special device test structures and novel material synthe- sis. Factors affecting the reliability of PCM are discussed.
-
Phase Change materials : science and applications
2009Co-Authors: Simone Raoux, Matthias WuttingAbstract:History of Phase Change Memories.- History of Phase Change Memories.- Material Science: Theory and Experiment.- Density Functional Theory Calculations for Phase Change Materials.- Nature of Glasses.- Structure of Amorphous Ge-Sb-Te Solids.- Experimental Methods for Material Selection in Phase-Change Recording.- Scaling Properties of Phase Change Materials.- Crystallization Kinetics.- Short and Long-Range Order in Phase Change Materials.- Optical and Electrical Properties of Phase Change Materials.- Development of Materials for Third Generation Optical Storage Media.- Novel Deposition Methods.- Applications: Optical, Solid State Memory and Reconfigurable Logic.- Optical Memory: From 1st to 3rd Generation and its Future.- 4th Generation Optical Memories Based on Super-resolution Near-field structure (Super-RENS) and Near-field Optics.- Phase Change Memory Device Modeling.- Phase Change Random Access Memory Advanced Prototype Devices and Scaling.- Phase Change Memory Cell Concepts and Designs.- Phase Change Random Access Memory Integration.- Reconfigurable Logic.
-
crystallization properties of ultrathin Phase Change films
Journal of Applied Physics, 2008Co-Authors: Simone Raoux, J Jordansweet, A J KellockAbstract:The crystallization behavior of ultrathin Phase Change films was studied using time-resolved x-ray diffraction (XRD). Thin films of variable thickness between 1 and 50nm of the Phase Change materials Ge2Sb2Te5 (GST), N-doped GST, Ge15Sb85, Sb2Te, and Ag- and In-doped Sb2Te were heated in a He atmosphere, and the intensity of the diffracted x-ray peaks was recorded. It was found for all materials that the crystallization temperature increases as the film thickness is reduced below 10nm. The increase depends on the material and can be as high as 200°C for the thinnest films. The thinnest films that show XRD peaks are 2nm for GST and N-GST, 1.5nm for Sb2Te and AgIn-Sb2Te, and 1.3nm for GeSb. This scaling behavior is very promising for the application of Phase Change materials to solid-state memory technology.
-
Phase-Change random access memory: A scalable technology
IBM Journal of Research and Development, 2008Co-Authors: Simone Raoux, Matthew J. Breitwisch, Daniel Krebs, Martin Salinga, Charles T. Rettner, Geoffrey W. Burr, Robert M. Shelby, S.-h. Chen, Hsiang-lan LungAbstract:Nonvolatile RAM using resistance contrast in Phase-Change materials [or Phase-Change RAM (PCRAM)] is a promising technology for future storage-class memory. However, such a technology can succeed only if it can scale smaller in size, given the increasingly tiny memory cells that are projected for future technology nodes (i.e., generations). We first discuss the critical aspects that may affect the scaling of PCRAM, including materials properties, power consumption during programming and read operations, thermal cross-talk between memory cells, and failure mechanisms. We then discuss experiments that directly address the scaling properties of the Phase-Change materials themselves, including studies of Phase transitions in both nanoparticles and ultrathin films as a function of particle size and film thickness. This work in materials directly motivated the successful creation of a series of prototype PCRAM devices, which have been fabricated and tested at Phase-Change material cross-sections with extremely small dimensions as low as 3 nm × 20 nm. These device measurements provide a clear demonstration of the excellent scaling potential offered by this technology, and they are also consistent with the scaling behavior predicted by extensive device simulations. Finally, we discuss issues of device integration and cell design, manufacturability, and reliability.
