In-situ Characterization of Switching Mechanism in Phase Change Random Access Memory (PRAM) Using Transmission Electron Microscopy (TEM)

2013 ◽  
Author(s):  
Sungkyu Son ◽  
Seungjoon Jeon ◽  
Jangwon Oh ◽  
Won Kim ◽  
Hojoung Kim ◽  
...  
Keyword(s):  
Phase Transition ◽  
Failure Analysis ◽  
Phase Change ◽  
Void Formation ◽  
Amorphous State ◽  
Random Access ◽  
Switching Behavior ◽  
In Situ Tem ◽  
Switching Mechanism

Abstract It is important to understand the switching mechanism of phase change material for failure analysis of PRAM device. In this study, the real time observations of phase transition and void formation mechanism of confined GST structure were investigated using in-situ TEM with multi-pulse AC biasing technique. In-situ SET switching behavior between amorphous state and crystalline state with continuous structural change was successfully observed. Volume shrink of GST, due to the phase transition, induced voids at grain boundary of crystalline phase. Excess Joule-heating after crystallization caused coalescence and migration of voids. These results may give us a crucial clue for endurance failure analysis of PRAM.

scholarly journals In situ TEM observation of void formation and migration in phase change memory devices with confined nanoscale Ge2Sb2Te5

2020 ◽  
Vol 2 (9) ◽  
pp. 3841-3848
Author(s):  
Sang Ho Oh ◽  
Kyungjoon Baek ◽  
Sung Kyu Son ◽  
Kyung Song ◽  
Jang Won Oh ◽  
...  
Keyword(s):  
Phase Change ◽  
Phase Change Memory ◽  
Void Formation ◽  
In Situ Tem ◽  
Memory Devices ◽  
Device Failure ◽  
And Migration ◽  
Change Memory

Void formation and migration that drive the device failure of Ge2Sb2Te5 (GST)-based practical devices were revealed via in situ TEM.

scholarly journals Microstructure-dependent DC set switching behaviors of Ge–Sb–Te-based phase-change random access memory devices accessed by in situ TEM

2015 ◽  
Vol 7 (6) ◽  
pp. e194-e194 ◽  
Author(s):  
Kyungjoon Baek ◽  
Kyung Song ◽  
Sung Kyu Son ◽  
Jang Won Oh ◽  
Seung-Joon Jeon ◽  
...  
Keyword(s):  
Phase Change ◽  
Random Access ◽  
Random Access Memory ◽  
In Situ Tem ◽  
Memory Devices ◽  
Access Memory ◽  
Set Switching

scholarly journals The Effect of Channel Length on Phase Transition of Phase Change Memory

2018 ◽  
Vol 7 (3.11) ◽  
pp. 25
Author(s):  
M S. A.Aziz ◽  
F H. M.Fauzi ◽  
Z Mohamad ◽  
R I. Alip
Keyword(s):  
Phase Transition ◽  
Silicon Carbide ◽  
Phase Change ◽  
Pulse Width ◽  
Crystalline State ◽  
Phase Change Memory ◽  
Amorphous State ◽  
Channel Length ◽  
Change Memory

The phase transition of germanium antimony tellurium (GST) and the temperature of GST were investigated using COMSOL Multiphysic 5.0 software. Silicon carbide was using as a heater layer in the separate heater structure of PCM. These simulations have a different channel of SiC. The temperature of GST and the phase transition of GST can be obtained from the simulation. From the simulation, the 300 nm channel of SiC can change the GST from amorphous to crystalline state at 0.7V with 100 ns pulse width. The 800 nm channel of SiC can change the GST from amorphous to crystalline state at 1.1V with 100 ns pulse width. Results demonstrated that the channel of SIC can affecting the temperature of GST and the GST changes from amorphous state to crystalline state. As the channel of SiC decreased, the temperature of GST was increased and the GST was change to crystalline state quickly.  

THERMAL EXPANSION OF PHASE-CHANGE RANDOM ACCESS MEMORY CELLS

2008 ◽  
Vol 1072 ◽  
Author(s):  
Jianming Li ◽  
L.P. Shi ◽  
H.X. Yang ◽  
K.G. Lim ◽  
X.S. Miao ◽  
...  
Keyword(s):  
Thermal Stress ◽  
Phase Change ◽  
Electrical Power ◽  
Thermal Strain ◽  
Three Dimensional ◽  
Amorphous State ◽  
Random Access ◽  
Random Access Memory ◽  
Access Memory ◽  
Three Dimensional Finite Element

ABSTRACTThree-dimensional finite element method (FEM) is used to solve the thermal strain-stress fields of phase-change random access memory (PCRAM) cells. Simulation results show that thermal stress concentrates at the interfaces between electrodes and phase change layer and it is significantly larger than that within the phase change layer. It has been found that the peak thermal stress is linearly related to the voltage of electrical pulse in the reset process but once amorphous state is produced in the cell, a nonlinear relationship between thermal stress and electrical power exists. This paper reported the change of thermal stress during set process. It was found that the stress decreases significantly due to the amorphous active region during set processes.

In situ TEM and half cell investigation of sodium storage in hexagonal FeSe nanoparticles

2019 ◽  
Vol 55 (39) ◽  
pp. 5611-5614 ◽  
Author(s):  
Kai Wu ◽  
Fei Chen ◽  
Zhongtao Ma ◽  
Bingkun Guo ◽  
Yingchun Lyu ◽  
...  
Keyword(s):  
Phase Transition ◽  
Electrochemical Performance ◽  
Tetragonal Phase ◽  
Sodium Ion ◽  
In Situ Tem ◽  
Sodium Ion Batteries ◽  
Half Cell ◽  
Sodium Storage

A hexagonal FeSe anode for sodium-ion batteries shows desirable electrochemical performance with an irreversible phase transition from the hexagonal to tetragonal phase.

scholarly journals Shape-preserving amorphous-to-crystalline transformation of CaCO3 revealed by in situ TEM

2020 ◽  
Vol 117 (7) ◽  
pp. 3397-3404 ◽  
Author(s):  
Zhaoming Liu ◽  
Zhisen Zhang ◽  
Zheming Wang ◽  
Biao Jin ◽  
Dongsheng Li ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Biological Fluids ◽  
Amorphous State ◽  
In Situ Tem ◽  
Dependent Manner ◽  
Amorphous Calcium Carbonate ◽  
Shape Preserving ◽  
Structural Water ◽  
Concentration Dependent Manner

Organisms use inorganic ions and macromolecules to regulate crystallization from amorphous precursors, endowing natural biominerals with complex morphologies and enhanced properties. The mechanisms by which modifiers enable these shape-preserving transformations are poorly understood. We used in situ liquid-phase transmission electron microscopy to follow the evolution from amorphous calcium carbonate to calcite in the presence of additives. A combination of contrast analysis and infrared spectroscopy shows that Mg ions, which are widely present in seawater and biological fluids, alter the transformation pathway in a concentration-dependent manner. The ions bring excess (structural) water into the amorphous bulk so that a direct transformation is triggered by dehydration in the absence of morphological changes. Molecular dynamics simulations suggest Mg-incorporated water induces structural fluctuations, allowing transformation without the need to nucleate a separate crystal. Thus, the obtained calcite retains the original morphology of the amorphous state, biomimetically achieving the morphological control of crystals seen in biominerals.

In situ TEM observing structural transitions of MoS2upon sodium insertion and extraction

RSC Advances ◽  
2016 ◽  
Vol 6 (98) ◽  
pp. 96035-96038 ◽  
Author(s):  
Liqiang Zhang ◽  
Yushu Tang ◽  
Yuecun Wang ◽  
Yongli Duan ◽  
Degang Xie ◽  
...  
Keyword(s):  
Phase Transition ◽  
In Situ Tem ◽  
Structural Transitions ◽  
Na Ions

The sodiation and desodiation process of MoS2was characterized by in situ TEM technique. The structural evolutions of MoS2, especially its phase transition from 2H to 1T-MoS2and the occupancy of the Na ions during the intercalation are recognized.

scholarly journals Resistive switching mechanism in the one diode-one resistor memory based on p+-Si/n-ZnO heterostructure revealed by in-situ TEM

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Lei Zhang ◽  
Liang Zhu ◽  
Xiaomei Li ◽  
Zhi Xu ◽  
Wenlong Wang ◽  
...  
Keyword(s):  
Resistive Switching ◽  
In Situ Tem ◽  
Switching Mechanism ◽  
The One ◽  
Resistive Switching Mechanism

scholarly journals Switching operation and degradation of resistive random access memory composed of tungsten oxide and copper investigated using in-situ TEM

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Masashi Arita ◽  
Akihito Takahashi ◽  
Yuuki Ohno ◽  
Akitoshi Nakane ◽  
Atsushi Tsurumaki-Fukuchi ◽  
...  
Keyword(s):  
Tungsten Oxide ◽  
Random Access ◽  
Random Access Memory ◽  
Resistive Random Access Memory ◽  
In Situ Tem ◽  
Access Memory ◽  
Switching Operation

Phase Transition Characteristics and Device Performance of Sn-doped Ge2Sb2Te5in Phase Change Random Access Memory

2006 ◽  
Vol 45 (No. 48) ◽  
pp. L1273-L1276 ◽  
Author(s):  
Tae Jin Park ◽  
Dae Hyun Kim ◽  
Sung Min Yoon ◽  
Kyu Jeong Choi ◽  
Nam Yeal Lee ◽  
...  
Keyword(s):  
Phase Transition ◽  
Phase Change ◽  
Random Access ◽  
Random Access Memory ◽  
Device Performance ◽  
Access Memory
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