scholarly journals Simulation-based calculations of the proton dose in phase change memory cells

2013 ◽  
Vol 28 (3) ◽  
pp. 299-307
Author(s):  
Nevena Zdjelarevic ◽  
Ivan Knezevic ◽  
Milos Vujisic ◽  
Ljubinko Timotijevic
Keyword(s):  
Active Region ◽  
Phase Change ◽  
Phase Change Materials ◽  
Phase Change Memory ◽  
Memory Cell ◽  
Memory Cells ◽  
Atomic Displacements ◽  
Radiation Induced ◽  
Proton Dose ◽  
Change Memory

Monte Carlo simulations of proton irradiation on phase change memory cells were conducted and the proton dose, in both the whole memory cell and in its active layer, calculated. The memory cell was modeled by a multi-layer stack consisting of two TiW electrodes and ZnS-SiO2 films as insulators surrounding the active region. Materials considered for the active region were Ge2Sb2Te5, AgSbSe2, and Si2Sb2Te5. The effects of exposing phase change memory cells to proton beams were investigated for various thicknesses of phase change materials and different proton energies. Radiation-induced changes in the investigated memory cells are presented, including the accumulation of atomic displacements and the thermal heating of the active region. Possible effects of these changes on cell operation are discussed.

Design of an Initialization Circuit Used in Phase Change Memory Chip

2014 ◽  
Vol 543-547 ◽  
pp. 471-474
Author(s):  
Qian Wang ◽  
Hou Peng Chen ◽  
Yi Yun Zhang ◽  
Xi Fan ◽  
Xi Li ◽  
...  
Keyword(s):  
Phase Change ◽  
High Resistance ◽  
Phase Change Materials ◽  
Phase Change Memory ◽  
Memory Cells ◽  
Memory Chip ◽  
Grain Sizes ◽  
Reset Operation ◽  
Materials Used ◽  
Change Memory

Design of a novel initialization circuit is presented in this paper. The initialization circuit is used to supply initialization current to the first test of phase change memory chip after delivery. Inhomogeneous crystalline grain sizes appear in phase change materials used in memory cells during manufacturing process. The crystalline phase with low resistance will convert to amorphous phase with high resistance after initialization, which is called RESET the memory cells to 0. Normal RESET operation current is not high enough to RESET great grain, which deteriorates bit yield of phase change memory chip. In comparison, the higher initialization current will increase bit yield observably.

scholarly journals Enhancing Programming Variability in Multi-Bit Phase Change Memory Cells for Security

2020 ◽  
Vol 19 ◽  
pp. 820-828
Author(s):  
Nafisa Noor ◽  
Sadid Muneer ◽  
Raihan Sayeed Khan ◽  
Anna Gorbenko ◽  
Helena Silva
Keyword(s):  
Phase Change ◽  
Phase Change Memory ◽  
Memory Cells ◽  
Change Memory

A SPICE model for a phase-change memory cell based on the analytical conductivity model

2012 ◽  
Vol 33 (11) ◽  
pp. 114004
Author(s):  
Yiqun Wei ◽  
Xinnan Lin ◽  
Yuchao Jia ◽  
Xiaole Cui ◽  
Jin He ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Memory ◽  
Memory Cell ◽  
Conductivity Model ◽  
Spice Model ◽  
Change Memory

Modeling of Set and Reset Operations of Phase-Change Memory Cells

2011 ◽  
Vol 32 (12) ◽  
pp. 1737-1739 ◽  
Author(s):  
Azer Faraclas ◽  
Nicholas Williams ◽  
Ali Gokirmak ◽  
Helena Silva
Keyword(s):  
Phase Change ◽  
Phase Change Memory ◽  
Memory Cells ◽  
Change Memory

scholarly journals Scalability of Phase Change Materials in Nanostructure Template

2015 ◽  
Vol 2015 ◽  
pp. 1-4
Author(s):  
Wei Zhang ◽  
Biyun L. Jackson ◽  
Ke Sun ◽  
Jae Young Lee ◽  
Shyh-Jer Huang ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Materials ◽  
Scaling Limit ◽  
Phase Change Memory ◽  
Leakage Power ◽  
Memory Element ◽  
Transmission Electron ◽  
Diffraction Mode ◽  
Memory Applications ◽  
Change Memory

The scalability of In2Se3, one of the phase change materials, is investigated. By depositing the material onto a nanopatterned substrate, individual In2Se3nanoclusters are confined in the nanosize pits with well-defined shape and dimension permitting the systematic study of the ultimate scaling limit of its use as a phase change memory element. In2Se3of progressively smaller volume is heated inside a transmission electron microscope operating in diffraction mode. The volume at which the amorphous-crystalline transition can no longer be observed is taken as the ultimate scaling limit, which is approximately 5 nm3for In2Se3. The physics for the existence of scaling limit is discussed. Using phase change memory elements in memory hierarchy is believed to reduce its energy consumption because they consume zero leakage power in memory cells. Therefore, the phase change memory applications are of great importance in terms of energy saving.

Simulation and Design of a Silicon Nanowire based Phase Change Memory Cell

2012 ◽  
Vol 1431 ◽  
Author(s):  
Ramin Banan Sadeghian ◽  
Yusuf Leblebici ◽  
Ali Shakouri
Keyword(s):  
Phase Change ◽  
High Speed ◽  
Low Cost ◽  
Silicon Nanowire ◽  
Phase Change Memory ◽  
Random Access ◽  
Memory Cell ◽  
Oxide Thickness ◽  
Nanowire Diameter ◽  
Change Memory

ABSTRACTIn this work we present preliminary calculations and simulations to demonstrate feasibility of programming a nanoscale Phase Change Random Access Memory (PCRAM) cell by means of a silicon nanowire ballistic transistor (SNWBT). Memory cells based on ballistic transistors bear the advantage of having a small size and high-speed operation with low power requirements. A one-dimensional MOSFET model (FETToy) was used to estimate the output current of the nanowire as a function of its diameter. The gate oxide thickness was 1.5 nm, and the Fermi level at source was set to -0.32 eV. For the case of VDS = VGS = 1 V, when the nanowire diameter was increased from 1 to 60 nm, the output power density dropped from 109 to 106 W cm-2 , while the current increased from 20 to 90 μA. Finite element electro-thermal analysis were carried out on a segmented cylindrical phase-change memory cell made of Ge2Sb2Te5 (GST) chalcogenide, connected in series to the SNWBT. The diameter of the combined device, d, and the aspect ratio of the GST region were selected so as to achieve optimum heating of the GST. With the assumption that the bulk thermal conductivity of GST does not change significantly at the nanoscale, it was shown that for d = 24 nm, a ‘reset’ programming current of ID = 80 μA can heat the GST up to its melting point. The results presented herein can help in the design of low cost, high speed, and radiation tolerant nanoscale PCRAM devices.

scholarly journals Plasmonic nanogap enhanced phase-change devices with dual electrical-optical functionality

2019 ◽  
Vol 5 (11) ◽  
pp. eaaw2687 ◽  
Author(s):  
Nikolaos Farmakidis ◽  
Nathan Youngblood ◽  
Xuan Li ◽  
James Tan ◽  
Jacob L. Swett ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Memory ◽  
Memory Cell ◽  
Communications Technologies ◽  
New Strategy ◽  
On Chip ◽  
Processing And Storage ◽  
Electrical Signaling ◽  
And Storage ◽  
Change Memory

Modern-day computers rely on electrical signaling for the processing and storage of data, which is bandwidth-limited and power hungry. This fact has long been realized in the communications field, where optical signaling is the norm. However, exploiting optical signaling in computing will require new on-chip devices that work seamlessly in both electrical and optical domains, without the need for repeated electrical-to-optical conversion. Phase-change devices can, in principle, provide such dual electrical-optical operation, but assimilating both functionalities into a single device has so far proved elusive owing to conflicting requirements of size-limited electrical switching and diffraction-limited optical response. Here, we combine plasmonics, photonics, and electronics to deliver an integrated phase-change memory cell that can be electrically or optically switched between binary or multilevel states. Crucially, this device can also be simultaneously read out both optically and electrically, offering a new strategy for merging computing and communications technologies.

Phase Change Memory Cell Concepts and Designs

2009 ◽  
pp. 355-380 ◽  
Author(s):  
Roberto Bez ◽  
Robert J. Gleixner ◽  
Fabio Pellizzer ◽  
Agostino Pirovano ◽  
Greg Atwood
Keyword(s):  
Phase Change ◽  
Phase Change Memory ◽  
Memory Cell ◽  
Change Memory
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