Unconventional phase transition of phase-change-memory materials for optical data storage

Scanning probe phase-change memory (SPPCM) has been widely considered as one of the most promising candidates for next-generation data storage devices due to its fast switching time, low power consumption, and potential for ultra-high density. Development of a comprehensive model able to accurately describe all the physical processes involved in SPPCM operations is therefore vital to provide researchers with an effective route for device optimization. In this paper, we introduce a pseudo-three-dimensional model to simulate the electrothermal and phase-transition phenomena observed during the SPPCM writing process by simultaneously solving Laplace’s equation to model the electrical process, the classical heat transfer equation, and a rate equation to model phase transitions. The crystalline bit region of a typical probe system and the resulting current-voltage curve obtained from simulations of the writing process showed good agreement with experimental results obtained under an equivalent configuration, demonstrating the validity of the proposed model.

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

International Journal of Engineering & Technology ◽

10.14419/ijet.v7i3.11.15923 ◽

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.

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Nonthermal phase transition in phase change memory cells induced by picosecond electric pulse

Applied Physics Letters ◽

10.1063/1.3597792 ◽

2011 ◽

Vol 98 (24) ◽

pp. 242106 ◽

Cited By ~ 21

Author(s):

D. Q. Huang ◽

X. S. Miao ◽

Z. Li ◽

J. J. Sheng ◽

J. J. Sun ◽

...

Keyword(s):

Phase Transition ◽

Phase Change ◽

Electric Pulse ◽

Phase Change Memory ◽

Memory Cells ◽

Change Memory

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Crystallization process of Ag-Sb-Te alloy and films for phase-change optical data storage

10.1117/12.462660 ◽

2002 ◽

Author(s):

Yagya D. Sharma ◽

Promod K. Bhatnagar

Keyword(s):

Phase Change ◽

Data Storage ◽

Crystallization Process ◽

Optical Data Storage ◽

Optical Data

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Phase transition characteristics of Al-Sb phase change materials for phase change memory application

Applied Physics Letters ◽

10.1063/1.4818662 ◽

2013 ◽

Vol 103 (7) ◽

pp. 072114 ◽

Cited By ~ 36

Author(s):

Xilin Zhou ◽

Liangcai Wu ◽

Zhitang Song ◽

Feng Rao ◽

Kun Ren ◽

...

Keyword(s):

Phase Transition ◽

Phase Change ◽

Phase Change Materials ◽

Phase Change Memory ◽

Change Memory

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A Novel Approach to Obtain GeSbTe-Based High Speed Crystallizing Materials for Phase Change Optical Recording

MRS Proceedings ◽

10.1557/proc-674-v1.7 ◽

2001 ◽

Vol 674 ◽

Cited By ~ 2

Author(s):

Tae-Yon Lee ◽

Byung-ki Cheong ◽

Taek Sung Lee ◽

Sung Jin Park ◽

Won Mok Kim ◽

...

Keyword(s):

Phase Change ◽

Data Storage ◽

High Speed ◽

Preliminary Test ◽

Optical Data Storage ◽

Optical Recording ◽

Optical Data ◽

Recording Layer ◽

Novel Approach ◽

Vegard’S Law

ABSTRACTA new approach is proposed to obtain fast crystallizing materials based on a conventional GeSbTe alloy for rewritable phase change optical data storage. By means of co-sputtering, Ge1Sb2Te4alloy was mixed with Sn1Bi2Te4alloy so as to form pseudo-binary alloys (Ge1Sb2Te4)1-x(Sn1Bi2Te4)x (x is a mole fraction). From structural and optical analyses of the co- sputtered and annealed alloy films, the formation of stable crystalline single phases was observed along with a Vegard's law behavior, suggesting a homogeneous mixing of the two alloys. By use of a 4 layered disk with (Ge1Sb2Te4)0.85(Sn1Bi2Te4)0.15 recording layer, a preliminary test of writing and erasing was carried out and the results were compared with the case of the disk with Ge1Sb2Te4recording layer. The (Ge1Sb2Te4)0.85(Sn1Bi2Te4)0.15 recording layer was found to yield markedly higher erasibility, especially with increasing disk linear velocity.

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Threshold switching and phase transition numerical models for phase change memory simulations

Journal of Applied Physics ◽

10.1063/1.2931951 ◽

2008 ◽

Vol 103 (11) ◽

pp. 111101 ◽

Cited By ~ 169

Author(s):

A. Redaelli ◽

A. Pirovano ◽

A. Benvenuti ◽

A. L. Lacaita

Keyword(s):

Phase Transition ◽

Phase Change ◽

Numerical Models ◽

Phase Change Memory ◽

Threshold Switching ◽

Change Memory

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Structural Transitions in Ge2Sb2Te5 Phase Change Memory Thin Films Induced by Nanosecond UV Optical Pulses

Materials ◽

10.3390/ma13092082 ◽

2020 ◽

Vol 13 (9) ◽

pp. 2082

Author(s):

Mario Behrens ◽

Andriy Lotnyk ◽

Hagen Bryja ◽

Jürgen W. Gerlach ◽

Bernd Rauschenbach

Keyword(s):

Thin Films ◽

Phase Transitions ◽

Phase Change ◽

Data Storage ◽

Structural Changes ◽

Phase Change Memory ◽

Phase Changes ◽

Uv Laser ◽

Optical Pulses ◽

Change Memory

Ge-Sb-Te-based phase change memory alloys have recently attracted a lot of attention due to their promising applications in the fields of photonics, non-volatile data storage, and neuromorphic computing. Of particular interest is the understanding of the structural changes and underlying mechanisms induced by short optical pulses. This work reports on structural changes induced by single nanosecond UV laser pulses in amorphous and epitaxial Ge2Sb2Te5 (GST) thin films. The phase changes within the thin films are studied by a combined approach using X-ray diffraction and transmission electron microscopy. The results reveal different phase transitions such as crystalline-to-amorphous phase changes, interface assisted crystallization of the cubic GST phase and structural transformations within crystalline phases. In particular, it is found that crystalline interfaces serve as crystallization templates for epitaxial formation of metastable cubic GST phase upon phase transitions. By varying the laser fluence, GST thin films consisting of multiple phases and different amorphous to crystalline volume ratios can be achieved in this approach, offering a possibility of multilevel data storage and realization of memory devices with very low resistance drift. In addition, this work demonstrates amorphization and crystallization of GST thin films by using only one UV laser with one single pulse duration and one wavelength. Overall, the presented results offer new perspectives on switching pathways in Ge-Sb-Te-based materials and show the potential of epitaxial Ge-Sb-Te thin films for applications in advanced phase change memory concepts.

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