An engineering model for high-speed switching in GeSbTe phase-change memory

2022 ◽  
Author(s):  
Junji TOMINAGA
Keyword(s):  
Phase Change ◽  
High Speed ◽  
High Performance ◽  
Ab Initio Molecular Dynamics ◽  
Switching Speed ◽  
Non Volatile Memory ◽  
Crystal Transition ◽  
Dynamics Simulations ◽  
High Speed Switching ◽  
Successful Phase

Abstract Ge2Sb2Te5 is the most successful phase-change alloy in non-volatile memory using the amorphous-crystal phase transition. In deriving further high performance in switching, especially SET speed (from amorphous to crystal transition) should still be modified. In this work, It was examined an ideal Ge2Sb2Te5 alloy based on the Kolobov model using ab-initio molecular dynamics simulations. As a result, it was cleared that a uniaxial exchange between vacancies and Ge atoms is the crucial role in realizing high-speed switching and a large contrast in the resonance bonding state in the alloy. The vacancy engineering enables the alloy switching speed extremely faster.

scholarly journals Ab initio molecular dynamics and materials design for embedded phase-change memory

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Liang Sun ◽  
Yu-Xing Zhou ◽  
Xu-Dong Wang ◽  
Yu-Han Chen ◽  
Volker L. Deringer ◽  
...  
Keyword(s):  
Phase Change ◽  
High Performance ◽  
Materials Design ◽  
Atomic Scale ◽  
Ab Initio Molecular Dynamics ◽  
Core Material ◽  
Structure Property ◽  
Switching Speed ◽  
Atomic Structures ◽  
Memory Applications

AbstractThe Ge2Sb2Te5 alloy has served as the core material in phase-change memories with high switching speed and persistent storage capability at room temperature. However widely used, this composition is not suitable for embedded memories—for example, for automotive applications, which require very high working temperatures above 300 °C. Ge–Sb–Te alloys with higher Ge content, most prominently Ge2Sb1Te2 (‘212’), have been studied as suitable alternatives, but their atomic structures and structure–property relationships have remained widely unexplored. Here, we report comprehensive first-principles simulations that give insight into those emerging materials, located on the compositional tie-line between Ge2Sb1Te2 and elemental Ge, allowing for a direct comparison with the established Ge2Sb2Te5 material. Electronic-structure computations and smooth overlap of atomic positions (SOAP) similarity analyses explain the role of excess Ge content in the amorphous phases. Together with energetic analyses, a compositional threshold is identified for the viability of a homogeneous amorphous phase (‘zero bit’), which is required for memory applications. Based on the acquired knowledge at the atomic scale, we provide a materials design strategy for high-performance embedded phase-change memories with balanced speed and stability, as well as potentially good cycling capability.

Octopus + : An RDMA-Enabled Distributed Persistent Memory File System

2021 ◽  
Vol 17 (3) ◽  
pp. 1-25
Author(s):  
Bohong Zhu ◽  
Youmin Chen ◽  
Qing Wang ◽  
Youyou Lu ◽  
Jiwu Shu
Keyword(s):  
High Speed ◽  
High Performance ◽  
File System ◽  
Direct Memory Access ◽  
File Systems ◽  
Distributed File Systems ◽  
Persistent Memory ◽  
Memory Modules ◽  
Non Volatile Memory ◽  
Volatile Memory

Non-volatile memory and remote direct memory access (RDMA) provide extremely high performance in storage and network hardware. However, existing distributed file systems strictly isolate file system and network layers, and the heavy layered software designs leave high-speed hardware under-exploited. In this article, we propose an RDMA-enabled distributed persistent memory file system, Octopus + , to redesign file system internal mechanisms by closely coupling non-volatile memory and RDMA features. For data operations, Octopus + directly accesses a shared persistent memory pool to reduce memory copying overhead, and actively fetches and pushes data all in clients to rebalance the load between the server and network. For metadata operations, Octopus + introduces self-identified remote procedure calls for immediate notification between file systems and networking, and an efficient distributed transaction mechanism for consistency. Octopus + is enabled with replication feature to provide better availability. Evaluations on Intel Optane DC Persistent Memory Modules show that Octopus + achieves nearly the raw bandwidth for large I/Os and orders of magnitude better performance than existing distributed file systems.

4H-SIC Dmosfets for High Frequency Power Switching Applications

2003 ◽  
Vol 764 ◽  
Author(s):  
Sei-Hyung Ryu ◽  
Anant K. Agarwal ◽  
James Richmond ◽  
John W. Palmour
Keyword(s):  
High Voltage ◽  
High Speed ◽  
High Performance ◽  
High Frequency Power ◽  
Power Devices ◽  
Power Switching ◽  
High Speed Switching ◽  
Unipolar Devices ◽  
Very High ◽  
Frequency Power

AbstractVery high critical field, reasonable bulk electron mobility, and high thermal conductivity make 4H-Silicon carbide very attractive for high voltage power devices. These advantages make high performance unipolar switching devices with blocking voltages greater than 1 kV possible in 4H-SiC. Several exploratory devices, such as vertical MOSFETs and JFETs, have been reported in SiC. However, most of the previous works were focused on high voltage aspects of the devices, and the high speed switching aspects of the SiC unipolar devices were largely neglected. In this paper, we report on the static and dynamic characteristics of our 4H-SiC DMOSFETs. A simple model of the on-state characteristics of 4H-SiC DMOSFETs is also presented.

OPTIMIZATION OF PHASE CHANGE MEMORY WITH THIN METAL INSERTED LAYER ON MATERIAL PROPERTIES

2009 ◽  
Vol 23 (17) ◽  
pp. 3625-3630 ◽  
Author(s):  
SANCHAI HARNSOONGNOEN ◽  
CHIRANUT SA-NGIAMSAK ◽  
APIRAT SIRITARATIWAT
Keyword(s):  
Finite Element ◽  
Electrical Resistivity ◽  
Phase Change ◽  
High Speed ◽  
Phase Change Memory ◽  
High Energy ◽  
Thin Metal ◽  
Non Volatile Memory ◽  
Element Approach ◽  
Change Memory

This works reports, for the first time, the thorough study and optimisation of Phase Change Memory (PCM) structure with thin metal inserted chalcogenide via electrical resistivity (ρ) using finite element modeling. PCM is one of the best candidates for next generation non-volatile memory. It has received much attention recently due to its fast write speed, non-destructive readout, superb scalability, and great compatibility with current silicon-based mass fabrication. The setback of PCM is a high reset current typically higher than 1mA based on 180nm lithography. To reduce the reset current and to solve the over-programming failure, PCM with thin metal inserted chalcogenide (bottom chalcogenide/metal inserted/top chalcogenide) structure has been proposed. Nevertheless, reports on optimisation of the electrical resistivity using the finite element method for this new PCM structure have never been published. This work aims to minimize the reset current of this PCM structure by optimizing the level of the electrical resistivity of the PCM profile using the finite element approach. This work clearly shows that PCM characteristics are strongly affected by the electrical resistivity. The 2-D simulation results reveal clearly that the best thermal transfer of and self-joule-heating at the bottom chalcogenide layer can be achieved under conditions; ρ_bottom chalcogenide > ρ_metal inserted > ρ_top chalcogenide More specifically, the optimized electrical resistivity of PCMTMI is attained with ρ_top chalcogenide: ρ_metal inserted: ρ_bottom chalcogenide ratio of 1:6:16 when ρ_top chalcogenide is 10-3 Ωm. In conclusion, high energy efficiency can be obtained with the reset current as low as 0.3mA and with high speed operation of less than 30ns.

scholarly journals Design of 2.5D Interposer in High Bandwidth Memory and Through Silicon Via for High Speed Signal

2020 ◽  
Author(s):  
Bo Pu
Keyword(s):  
Artificial Intelligence ◽  
High Speed ◽  
High Performance ◽  
Equivalent Model ◽  
Electrical Characteristics ◽  
Through Silicon Via ◽  
High Bandwidth ◽  
Signal Path ◽  
High Speed Switching ◽  
Performance Computing

<p>The 2.5D interposer becomes a crucial solution to realize grand bandwidth of HBM for the increasing data requirement of high performance computing (HPC) and Artificial Intelligence (AI) applications. To overcome high speed switching bottleneck caused by the large resistive and capacitive characteristics of interposer, design methods to achieve an optimized performance in a limited routing area are proposed. Unlike the conventional single through silicon via (TSV), considering the reliability, multiple TSV are used as the robust 3D interconnects for each signal path. An equivalent model to accurately describe the electrical characteristics of the multiple TSVs, and a configuration pattern strategy of TSV to mitigate crosstalk are also proposed.</p>

scholarly journals Biomechanics and hydrodynamics of prey capture in the Chinese giant salamander reveal a high-performance jaw-powered suction feeding mechanism

2013 ◽  
Vol 10 (82) ◽  
pp. 20121028 ◽  
Author(s):  
Egon Heiss ◽  
Nikolay Natchev ◽  
Michaela Gumpenberger ◽  
Anton Weissenbacher ◽  
Sam Van Wassenbergh
Keyword(s):  
High Speed ◽  
High Performance ◽  
Prey Capture ◽  
Three Dimensional ◽  
Cranial Morphology ◽  
Suction Feeding ◽  
Mechanical Constraints ◽  
Terrestrial Life ◽  
Chinese Giant Salamander ◽  
Dynamics Simulations

During the evolutionary transition from fish to tetrapods, a shift from uni- to bidirectional suction feeding systems followed a reduction in the gill apparatus. Such a shift can still be observed during metamorphosis of salamanders, although many adult salamanders retain their aquatic lifestyle and feed by high-performance suction. Unfortunately, little is known about the interplay between jaws and hyobranchial motions to generate bidirectional suction flows. Here, we study the cranial morphology, as well as kinematic and hydrodynamic aspects related to prey capture in the Chinese giant salamander ( Andrias davidianus ). Compared with fish and previously studied amphibians, A. davidianus uses an alternative suction mechanism that mainly relies on accelerating water by separating the ‘plates’ formed by the long and broad upper and lower jaw surfaces. Computational fluid dynamics simulations, based on three-dimensional morphology and kinematical data from high-speed videos, indicate that the viscerocranial elements mainly serve to accommodate the water that was given a sufficient anterior-to-posterior impulse beforehand by powerful jaw separation. We hypothesize that this modified way of generating suction is primitive for salamanders, and that this behaviour could have played an important role in the evolution of terrestrial life in vertebrates by releasing mechanical constraints on the hyobranchial system.

Exploring Na_5M(PO_4)_2 F_2 (M=Cr,V) Frameworks as Superionic Cathode Materials for Sodium Ion Batteries Through A First Principles Approach

2020 ◽  
Author(s):  
Madhulika Mazumder ◽  
Swapan K. Pati
Keyword(s):  
Cathode Materials ◽  
First Principles ◽  
Theoretical Basis ◽  
High Performance ◽  
Storage Systems ◽  
Sodium Ion ◽  
Ab Initio Molecular Dynamics ◽  
Sodium Ion Batteries ◽  
Ion Migration ◽  
Dynamics Simulations

The rising needs to develop high-performance energy storage systems fuelled us to rationally design a system of frameworks Na5M(PO4)2F2 (M=Cr, v), which can find use as Superionic cathode materials for Sodium Ion Batteries.<div>The findings of the work provide a theoretical basis with respect to their thermodynamics as well as Na ion migration kinetics. In addition to DFT studies, we have also performed Ab-Initio Molecular Dynamics simulations to obtain a more realistic understanding of the systems at finite temperatures. </div><div>We believe that this work is novel and has contemporary relevance.</div>

Exploring Na_5M(PO_4)_2 F_2 (M=Cr,V) Frameworks as Superionic Cathode Materials for Sodium Ion Batteries Through A First Principles Approach

2020 ◽  
Author(s):  
Madhulika Mazumder ◽  
Swapan K. Pati
Keyword(s):  
Cathode Materials ◽  
First Principles ◽  
Theoretical Basis ◽  
High Performance ◽  
Storage Systems ◽  
Sodium Ion ◽  
Ab Initio Molecular Dynamics ◽  
Sodium Ion Batteries ◽  
Ion Migration ◽  
Dynamics Simulations

The rising needs to develop high-performance energy storage systems fuelled us to rationally design a system of frameworks Na5M(PO4)2F2 (M=Cr, v), which can find use as Superionic cathode materials for Sodium Ion Batteries.<div>The findings of the work provide a theoretical basis with respect to their thermodynamics as well as Na ion migration kinetics. In addition to DFT studies, we have also performed Ab-Initio Molecular Dynamics simulations to obtain a more realistic understanding of the systems at finite temperatures. </div><div>We believe that this work is novel and has contemporary relevance.</div>

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