A5060746564- Phase-change materials and chalcogenides
- Chalcogenide Semiconductor Thin Films
- Liquid Crystal Research Advancements
- Advanced Memory and Neural Computing
- Nonlinear Optical Materials Studies
- Transition Metal Oxide Nanomaterials
- Solid-state spectroscopy and crystallography
- Electron and X-Ray Spectroscopy Techniques
- Glass properties and applications
- Quantum Dots Synthesis And Properties
- Advanced Electron Microscopy Techniques and Applications
- Graphene research and applications
- Topological Materials and Phenomena
- Semiconductor materials and devices
- Magnetic properties of thin films
- Advancements in Photolithography Techniques
- Nanofabrication and Lithography Techniques
- Advanced Semiconductor Detectors and Materials
- MXene and MAX Phase Materials
- Advanced Thermoelectric Materials and Devices
- Advancements in Battery Materials
- Theoretical and Computational Physics
- Block Copolymer Self-Assembly
- Perovskite Materials and Applications
- Thin-Film Transistor Technologies
Helmholtz-Zentrum Berlin für Materialien und Energie
2014-2024
Humboldt-Universität zu Berlin
2018-2021
Macronix International (Taiwan)
2009-2019
Oregon State University
2019
Lawrence Livermore National Laboratory
2013-2019
IBM (United States)
2003-2014
IBM Research - Thomas J. Watson Research Center
2006-2014
IBM Research - Almaden
2004-2013
Lawrence Berkeley National Laboratory
2010
École Polytechnique
2009
High-temperature solution phase reaction of iron(III) acetylacetonate, Fe(acac)3, with 1,2-hexadecanediol in the presence oleic acid and oleylamine leads to monodisperse magnetite (Fe3O4) nanoparticles. Similarly, Fe(acac)3 Co(acac)2 or Mn(acac)2 same diol results CoFe2O4 MnFe2O4 Particle diameter can be tuned from 3 20 nm by varying conditions seed-mediated growth. The as-synthesized iron oxide nanoparticles have a cubic spinel structure as characterized HRTEM, SAED, XRD. Further, Fe3O4...
In this paper, recent progress of phase change memory (PCM) is reviewed. The electrical and thermal properties materials are surveyed with a focus on the scalability their impact device design. Innovations in structure, cell selector, strategies for achieving multibit operation 3-D, multilayer high-density arrays described. scaling PCM illustrated experimental results using special test structures novel material synthesis. Factors affecting reliability discussed.
Nonvolatile RAM using resistance contrast in phase-change materials [or (PCRAM)] is a promising technology for future storage-class memory. However, such can succeed only if it scale smaller size, given the increasingly tiny memory cells that are projected nodes (i.e., generations). We first discuss critical aspects may affect scaling of PCRAM, including properties, power consumption during programming and read operations, thermal cross-talk between cells, failure mechanisms. then...
The authors survey the current state of phase change memory (PCM), a nonvolatile solid-state technology built around large electrical contrast between highly resistive amorphous and conductive crystalline states in so-called materials. PCM has made rapid progress short time, having passed older technologies terms both sophisticated demonstrations scaling to small device dimensions, as well integrated large-array demonstrators with impressive retention, endurance, performance, yield...
Phase change materials (PCMs) can exist in at least two different phases (an amorphous and one or more crystalline phases), they be switched repeatedly between these phases. The have distinctly physical properties such as electrical conductivity, optical reflectivity, mass density, thermal conductivity. These differences the repeatability of switching give ability to store information. Rewritable compact discs, digital versatile Blu-ray™ discs information thin films PCMs, using difference...
We discuss novel multi-level write algorithms for phase change memory which produce highly optimized resistance distributions in a minimum number of program cycles. Using integration scheme, test array at 4 bits/cell and 32 kb page 2 are experimentally demonstrated.
The crystallization behavior of ultrathin phase change films was studied using time-resolved x-ray diffraction (XRD). Thin variable thickness between 1 and 50nm the materials Ge2Sb2Te5 (GST), N-doped GST, Ge15Sb85, Sb2Te, Ag- In-doped Sb2Te were heated in a He atmosphere, intensity diffracted peaks recorded. It found for all that temperature increases as film is reduced below 10nm. increase depends on material can be high 200°C thinnest films. show XRD are 2nm GST N-GST, 1.5nm AgIn-Sb2Te,...
Phase transformation generally begins with nucleation, in which a small aggregate of atoms organizes into different structural symmetry. The thermodynamic driving forces and kinetic rates have been predicted by classical nucleation theory, but observation nanometer-scale nuclei has not possible, except on exposed surfaces. We used statistical technique called fluctuation transmission electron microscopy to detect embedded glassy solid, we laser pump-probe determine the role these...
The memory capacity, computational power, communication bandwidth, energy consumption, and physical size of the brain all tend to scale with number synapses, which outnumber neurons by a factor 10,000. Although progress in cortical simulations using modern digital computers has been rapid, essential disparity between classical von Neumann computer architecture fabric nervous system makes large-scale expensive, power hungry, time consuming. Over last three decades, CMOS-based neuromorphic...
The threshold switching effect of phase change memory devices is typically parameterized by the voltage at which this breakdown occurs. Using bridge variable length, we prove unambiguously that important parameter for a critical electrical field and not voltage. By from amorphous-as-deposited state, obtain fields Ge15Sb85, Ag- In-doped Sb2Te, Ge2Sb2Te5, 4 nm thick Sb 8.1, 19, 56, 94 V/μm, respectively.
An ultra-thin phase-change bridge (PCB) memory cell, implemented with doped GeSb, is shown < 100muA RESET current. The device concept provides for simplified scaling to small cross-sectional area (60nm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> ) through (3nm) films; the GeSb material offers potential both fast crystallization and good data retention
The crystallization times of Ge–Te phase change materials with variable Ge concentrations (29.5–72.4 at. %) were studied. A very strong dependence the time on composition for as-deposited, amorphous films was confirmed, a minimum stoichiometric GeTe. is weaker melt-quenched, material and are between one to almost four orders magnitude shorter than as-deposited materials. This promising applications because recrystallization from melt-quenched relevant process optical solid state memory, fast...
Colloidal nanocrystals have long been used to study the dependence of phase stability and transitions on size. Both structural change dramatically in nanometre size regime where surface plays a significant role determining overall energetics system. We investigate solid–solid transformation crystallization amorphous GeTe nanoparticles. report colloidal synthetic route Using situ X-ray diffraction while heating, we observe nanoparticles find dramatic increase temperature over 150 °C above...
The crystallization of amorphous Ge2Sb2Te5 (GST) doped with nitrogen is studied pulsed laser heating. time sputter-deposited films increased by doping as much 100× for concentrations the order 12 at. % in as-deposited films. Suppression formation critical crystal nuclei found to be responsible. melt-quenched material also slowed but less dramatically.
We have used time-resolved x-ray diffraction to study the amorphous-crystalline phase transition in 20–80nm particles of change materials Ge2Sb2Te5, nitrogen-doped Ge15Sb85, Sb2Te, and Sb2Te doped with Ag In. find that all samples undergo crystallization temperatures close those similarly prepared blanket films same exception shows at a temperature is about 40°C higher than films. Some nanoparticles show difference crystallographic texture compared thick Large area arrays these were...
Abstract Phase Change Materials are solids which characterized by a unique combination of properties. They exist in an amorphous and crystalline phase with remarkably different optical electrical properties caused unusual change bonding when the is crystallized. It possible to such material very short times (nanoseconds) repeatedly between two phases makes materials ideal candidates for data storage. This paper reviews detail relationship mechanisms resulting physical materials. describes...
The question of the nature and stability polar ordering in nanoscale ferroelectrics is examined with colloidal nanocrystals germanium telluride (GeTe). We provide atomic-scale evidence for room-temperature individual using aberration-corrected transmission electron microscopy demonstrate a reversible, size-dependent polar-nonpolar phase transition displacive character nanocrystal ensembles. A substantial linear component distortion observed, which contrast theoretical reports predicting...
Phase change memory devices are based on the rapid and reversible amorphous-to-crystalline transformations of phase materials, such as Ge2Sb2Te5 AgInSbTe. Since maximum switching speed these is typically limited by crystallization speed, understanding process crucial importance. While AgInSbTe show very different mechanisms from their melt-quenched states, nanostructural origin this difference has not been clearly demonstrated. Here, we that an amorphous state includes sizes number nanoscale...