January 27, 2021

Download Ebook Free Phase Change Memory

Phase Change Memory

Phase Change Memory
Author : Andrea Redaelli
Publisher : Springer
Release Date : 2017-11-18
Category : Technology & Engineering
Total pages :330
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This book describes the physics of phase change memory devices, starting from basic operation to reliability issues. The book gives a comprehensive overlook of PCM with particular attention to the electrical transport and the phase transition physics between the two states. The book also contains design engineering details on PCM cell architecture, PCM cell arrays (including electrical circuit management), as well as the full spectrum of possible future applications.

Phase Change Memory

Phase Change Memory
Author : Moinuddin K. Qureshi,Sudhanva Gurumurthi,Bipin Rajendran
Publisher : Morgan & Claypool Publishers
Release Date : 2011-11-01
Category : Computers
Total pages :120
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This book will educate readers on the theory and application of Phase-Change Memory (aka, PRAM, PCME, PCRAM, C-RAM, Chalcogenide RAM, and Ovonic Unified Memory). This non-volatile computer memory is a major competitor with the ubiquitous flash memory, which suffers from a number of practical problems that the newer Phase-Change Memory hopes to eradicate. This book is appropriate for professional researchers, graduate students, and advanced undergraduates.

Durable Phase-Change Memory Architectures

Durable Phase-Change Memory Architectures
Author : Anonim
Publisher : Academic Press
Release Date : 2020-02-21
Category : Computers
Total pages :146
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Advances in Computers, Volume 118, the latest volume in this innovative series published since 1960, presents detailed coverage of new advancements in computer hardware, software, theory, design and applications. Chapters in this updated release include Introduction to non-volatile memory technologies, The emerging phase-change memory, Phase-change memory architectures, Inter-line level schemes for handling hard errors in PCMs, Handling hard errors in PCMs by using intra-line level schemes, and Addressing issues with MLC Phase-change Memory. Gives a comprehensive overlook of new memory technologies, including PCM Provides reliability features with an in-depth discussion of physical mechanisms that are currently limiting PCM capabilities Covers the work of well-known authors and researchers in the field Includes volumes that are devoted to single themes or subfields of computer science

Nonvolatile Memory Design

Nonvolatile Memory Design
Author : Hai Li,Yiran Chen
Publisher : CRC Press
Release Date : 2017-12-19
Category : Computers
Total pages :203
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The manufacture of flash memory, which is the dominant nonvolatile memory technology, is facing severe technical barriers. So much so, that some emerging technologies have been proposed as alternatives to flash memory in the nano-regime. Nonvolatile Memory Design: Magnetic, Resistive, and Phase Changing introduces three promising candidates: phase-change memory, magnetic random access memory, and resistive random access memory. The text illustrates the fundamental storage mechanism of these technologies and examines their differences from flash memory techniques. Based on the latest advances, the authors discuss key design methodologies as well as the various functions and capabilities of the three nonvolatile memory technologies.

Phase Change Memory Cell Emulator Circuit Design

Phase Change Memory Cell Emulator Circuit Design
Author : Anonim
Publisher : Unknown
Release Date : 2017
Category :
Total pages :129
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Abstract: Thispaper presents a novel phase change memory (PCM) cell emulator circuit design created solely with off-the-shelf discrete electronic components. The designed emulator circuit reproduces PCM cell behavior in terms of temperature across the cell, threshold voltage, and programmed resistance levels in response to a given input. The presented circuit is designed and tested in simulation environment using LTSpice. The circuit was then built with CMOS 0.35 μm technology along with other off-the-shelf discrete components. The designed emulator circuit successfully generated the operational features of a PCM cell. The emulator circuit assessed the impact of the programming time, produced the standard I-V characteristics of a PCM element and retained the stored data throughout the duration of operation. Furthermore, the simulation and experimental results of the designed emulator circuit were found to be in close agreement with the experimental data obtained from an actual Ge2 Sb2 Te5 (GST) based PCM element.

Colloidal Nanoparticles for Phase Change Memory Applications

Colloidal Nanoparticles for Phase Change Memory Applications
Author : Anonim
Publisher : Stanford University
Release Date : 2011
Category :
Total pages :129
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Phase change (PC) memory has emerged as a leading candidate for next generation information storage technology. Based on the reversible amorphous-crystalline phase transition of chalcogenide materials, PC technology has already been commercialized through the optical disk industry and is currently being evaluated for non-volatile electronic data storage as phase change random access memory (PCRAM). In either the optical or electronic application, device performance relies on the material properties of the active phase change material (PCM). Traditionally deposited through physio-chemical routes such as sputtering or chemical vapor deposition, the PCM fundamentally limits PC scaling potential as it is expected that key properties will change as the volume of PCM decreases. Colloidal nanoparticle systems provide a unique opportunity to systematically study the properties of materials in the nanosize regime due to the potential for exquisite composition and size control. In this talk, I will present the first colloidal nanoparticle system of a known phase change material. Colloidal GeTe nanoparticles 1.4-4nm in diameter were synthesized through a co-precipitation route and characterized by transmission electron microscopy, energy dispersive x-ray spectroscopy and x-ray diffraction. Nuclear magnetic resonance spectroscopy (1H and 31P) was used to elucidate the molecular species involved in the reaction pathway and found that a metal center mediated proton transfer is necessary to mediate the relative reactivity of the reactants. In addition, a post-synthetic size selective procedure was developed to separate the nanoparticles into distinct size ranges. Using in-situ heating, the size dependent crystallization temperature was measured by XRD and was found to increase with decreasing nanoparticle diameter suggesting favorable improvements in lifetime data retention for scaled PCRAM cells. To evaluate the potential use in PCRAM devices, electrical measurements were also collected on nanoparticle films. Resistance versus temperature measurements revealed that nanoparticle films retained the high resistive contrast between the amorphous and crystalline phases necessary for PCRAM operation. After design optimization, PCRAM cells were fabricated utilizing the nanoparticles as a solution processable precursor to the PCM. Completed cells showed reversible switching, including threshold switching, characteristic of PCRAM operation. Cycling up to 200 times, the cells are the best performing solution processed PCRAM devices reported to date, suggesting that colloidal nanoparticles are a viable route to PCMs.

Exploiting Phase Change Memory Nano-device Properties for Hardware Security Applications

Exploiting Phase Change Memory Nano-device Properties for Hardware Security Applications
Author : Nafisa Noor
Publisher : Unknown
Release Date : 2019
Category : Electronic dissertations
Total pages :129
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Security has become a crucial concern in hardware design due to the growing need of protection in everyday financial transactions and exchanges of private information. Physical unclonable functions (PUFs) utilize the inevitable process variations and other stochastic properties in devices to provide a unique way to verify trusted users during access to hardware devices. Improvements in attack methods have recently moved the field of PUFs from traditional silicon devices toward emerging non-volatile memories, such as phase change memory (PCM). Due to intrinsic cell-to-cell and cycle-to-cycle programming variability and high endurance properties of PCM nano-devices, unpredictable and reconfigurable PUF challenge-response pairs can be achieved. This programming variability, which comes in addition to the process variations present in any technology, is an important advantage of PCM for implementations of PUFs and other hardware security primitives. In this work, programming variability in PCM nano-devices are electrically characterized using various cell dimensions and pulsing techniques for PUF applications. The underlying contributing factors, originating from external circuitry and phase change dynamics of PCM nano-devices, that enhance programming variability are identified by performing post-measurement scanning electron microscopy (SEM) imaging, further electrical characterization, SPICE modeling of the experimental setup, and finite element simulations of PCM devices. Once programmed, the short and long-term stability of the programmed states in PCM nano-devices is monitored, and the spontaneous resistance evolution trends for different cell types are studied, which helped in identifying the cell geometries that result in long data retention time for memory devices, and those that result in earlier data loss creating opportunities for new security applications, such as time-sensitive memory devices. The disturbance to the spontaneous resistance evolution at any programmed state caused by SEM imaging is also characterized. Imaging is observed to leave remarkable evidence of tampering posing resistance toward reverse engineering and ensuring robust security to the PCM-based nano-devices. Lastly, the reconfigurable source of randomness in PCM-based PUFs relying on programming variability is contrasted with a static source of randomness in a ZnO nanoforest-based PUF. The advantageous reconfigurability in PCM-based PUFs can ensure resistance toward physical attacks, which is not achieved with the ZnO nanoforest-based PUF.

Springer Handbook of Electronic and Photonic Materials

Springer Handbook of Electronic and Photonic Materials
Author : Safa Kasap,Peter Capper
Publisher : Springer
Release Date : 2017-10-04
Category : Technology & Engineering
Total pages :1536
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The second, updated edition of this essential reference book provides a wealth of detail on a wide range of electronic and photonic materials, starting from fundamentals and building up to advanced topics and applications. Its extensive coverage, with clear illustrations and applications, carefully selected chapter sequencing and logical flow, makes it very different from other electronic materials handbooks. It has been written by professionals in the field and instructors who teach the subject at a university or in corporate laboratories. The Springer Handbook of Electronic and Photonic Materials, second edition, includes practical applications used as examples, details of experimental techniques, useful tables that summarize equations, and, most importantly, properties of various materials, as well as an extensive glossary. Along with significant updates to the content and the references, the second edition includes a number of new chapters such as those covering novel materials and selected applications. This handbook is a valuable resource for graduate students, researchers and practicing professionals working in the area of electronic, optoelectronic and photonic materials.

Phase Change Materials

Phase Change Materials
Author : Simone Raoux,Matthias Wuttig
Publisher : Springer Science & Business Media
Release Date : 2010-06-10
Category : Technology & Engineering
Total pages :430
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"Phase Change Materials: Science and Applications" provides a unique introduction of this rapidly developing field. Clearly written and well-structured, this volume describes the material science of these fascinating materials from a theoretical and experimental perspective. Readers will find an in-depth description of their existing and potential applications in optical and solid state storage devices as well as reconfigurable logic applications. Researchers, graduate students and scientists with an interest in this field will find "Phase Change Materials" to be a valuable reference.

Mercury

Mercury
Author : Madhura Joshi
Publisher : Unknown
Release Date : 2010
Category :
Total pages :129
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ABSTRACT: Phase Change Memory (PCM) is one of the most promising technologies among emerging non-volatile memories. PCM stores data in crystalline and amorphous phases of GST material having large difference in their electrical resistivity. Though it is possible to design a high capacity memory system by storing multiple bits at intermediate levels between highest and lowest resistance state of PCM, it is difficult to obtain tight distribution required for correct reading of data. Moreover, the write latency and programming energy for an MLC PCM cell are not trivial and act as a major hurdle in applying multi-level PCM in high density memory architecture design. Effect of process variation (PV) on PCM cell exacerbates the variability in necessary programming current and hence the target resistance spread leading to the demand for high-latency, multi-iteration-based programming, write verify schemes for MLC-PCM. PV aware control of programming current, programming using staircase down pulses of current or increasing reset current pulses are some of the traditional techniques used to achieve optimum programming energy, write latency and better accuracy, but they are usually able to optimize only one aspect of the design. This work addresses the high write latency and process variation issue of MLC-PCM by introducing a fast and energy efficient multi-level cell based phase change memory architecture. This architecture adapts the programming scheme of a multi-level cell by considering the initial state of the cell, the target resistance to be programmed and the effect of process variation in programming current profile of the cell. The proposed techniques act at circuit as well as micro-architecture levels. Simulation results show that we achieve 10% saving in programming latency and 25% saving in programming energy for the PCM memory system compared to traditional methods.

Crystallization Kinetics of Sn40Se60 Thin Films for Phase Change Memory Applications

Crystallization Kinetics of Sn40Se60 Thin Films for Phase Change Memory Applications
Author : Anonim
Publisher : Unknown
Release Date : 2015
Category :
Total pages :129
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Phase-change memory in amorphous chalcogenide semiconductor

Phase-change memory in amorphous chalcogenide semiconductor
Author : Anonim
Publisher : Unknown
Release Date : 2003
Category :
Total pages :129
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Scalability and Reliability of Phase Change Memory

Scalability and Reliability of Phase Change Memory
Author : Anonim
Publisher : Stanford University
Release Date : 2010
Category :
Total pages :129
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Various memory devices are being widely used for a wide range of applications. There has not been any universal memory device so far because each memory device has a unique set of features. Large performance gaps in various dimensions of features between memory devices and a new set of features required by new electronic systems such as portable electronics open up new opportunities for new memory devices to emerge as mainstream memory devices. Besides, the imminent scaling limit for existing mainstream memory devices also motivates development and research of new memory devices which can meet the increasing demand for large memory capacity. Phase change memory (PCM) is one of the most promising emerging memory devices. It has the potential to combine DRAM-like features such as bit alteration, fast read and write, and good endurance and Flash-like features such as non-volatility and a simple structure. PCM is expected to be a highly scalable technology extending beyond scaling limit of existing memory devices. Prototypical PCM chips have been developed and are being tested for targeted memory applications. However, understanding of fundament physics behind PCM operation is still lacking because the key material in PCM devices, the chalcogenide, is relatively new for use in solid state devices. Evaluation and development of PCM technology as successful mainstream memory devices require more study on PCM devices. This thesis focuses on issues relevant to scalability and reliability of PCM which are two of the most important qualities that new emerging memory devices should demonstrate. We first study basic scaling rule based on thermoelectric analysis on the maximum temperature in a PCM cell and show that both isotropic and non-isotropic scaling result in constant programming voltage. The minimum programming voltage is determined by material properties such as electrical resistivity and thermal conductivity regardless of the device size. These results highlight first-order principles governing scaling rules. In the first-order scaling rule analysis, we assume that material properties are constant regardless of its physical size. However, when materials are scaled down to the nanometer regime, material properties can change because the relative contribution from the surface property to the overall system property increases compared to that from the bulk property. We study scaling effect on material property and device characteristics using a novel device structure -- a PCM cell with a pseudo electrode. With the pseudo electrode PCM cell, we can accurately relate the observed properties to the amorphous region size. We show that threshold switching voltage scales linearly with thickness of the amorphous region and threshold switching field drifts in time after programming. We also show that the drift coefficient for resistance drift stays the same for scaled devices. These property scaling results provide not only estimates for scaled device characteristics but also clues for modeling and understanding mechanisms for threshold switching and drift. To make scaled memory cells in an array form, not only memory device elements but also selection devices need to be scaled. PCM requires relatively large programming current, which makes it challenging to scale down selection devices. We integrate Ge nanowire diodes as selection devices in search for new candidates for high density PCM. Ge nanowire diode provides on/off ratio of ~100 and small contact area of 40 nm in diameter which results in programming current below 200 [mu]A. The processing temperature for Ge nanowire diode is below 400°C, which makes Ge nanowire diode a potential enabler for 3D integration. As memory devices are scaled down, more serious reliability issues arise. We study the reliability of PCM using a novel structure -- micro-thermal stage (MTS). The high-resistance-state (RESET) resistance and threshold switching voltage are important device characteristics for

Electrophysical Properties of Phase Change Memory Materials on the Pseudo-binary Line GeTe-Sb2Te3

Electrophysical Properties of Phase Change Memory Materials on the Pseudo-binary Line GeTe-Sb2Te3
Author : Anonim
Publisher : Unknown
Release Date : 2015
Category :
Total pages :129
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Abstract: The temperature dependences of the resistivity and current-voltage characteristics of amorphous thin films on the basis of GeSb4 Te7, GeSb2 Te4, and Ge2 Sb2 Te5 perspective for the phase change memory application were investigated. It was revealed that two-channel conduction mechanism with the transport of charge carriers by the localized states in the valence band tail and delocalized states of the valence band is characteristic feature of these materials.

Investigating the Switching Mechanism of Interfacial Phase Change Memory

Investigating the Switching Mechanism of Interfacial Phase Change Memory
Author : Kye Loren Okabe
Publisher : Unknown
Release Date : 2019
Category :
Total pages :129
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Phase Change Memory (PCM) is a leading candidate for next generation data storage, but it typically suffers from high switching (RESET) current density (20--30 MA/cm2). Interfacial Phase Change Memory (IPCM) is a type of PCM using multilayers of Sb2Te3/GeTe, with up to 100× lower reported RESET current compared to the standard Ge2Sb2Te5-based PCM. Several hypotheses involving fundamentally new switching mechanisms have been proposed to explain the low switching current densities, but consensus is lacking. IPCM switching is investigated by analyzing its thermal, electrical, and fabrication dependencies. First, the effective thermal conductivity (∼0.4 Wm−1K−1) and thermal boundary resistance (∼3.4 m2KGW−1) of Sb2Te3/GeTe multilayers is measured. Simulations show that IPCM thermal properties account only for ∼13% reduction of current vs standard PCM and cannot explain previously reported results. Interestingly, electrical measurements reveal that IPCM RESET indeed occurs by a melt-quench process, similar to PCM. High deposition temperatures are shown to cause defects including surface roughness and voids within the multilayer films. Thus, the substantial RESET current reduction of IPCM appears to be caused by voids within the multilayers, which migrate to the bottom electrode interface by thermophoresis, reducing the effective contact area. These results shed light on the IPCM switching mechanism, suggesting that an improved control of layer deposition is necessary to obtain reliable switching. Finally, finite element simulations are performed to predict time and volumetric scaling trends of PCM switching. Usage of pulse widths beyond a few nanoseconds are shown to be essentially wasting energy due to the time scales of device heating and is experimentally verified. Finally, current densities are predicted to become worse at ultra-scaled dimensions (bottom electrode diameter