Please use this identifier to cite or link to this item: https://doi.org/10.1016/j.apsusc.2012.03.005
Title: Temperature-dependent phase separation during annealing of Ge 2Sb 2Te 5 thin films in vacuum
Authors: Zhang, Z.
Pan, J.
Fang, L.W.-W.
Yeo, Y.-C. 
Foo, Y.L.
Zhao, R.
Shi, L.
Tok, E.S. 
Keywords: Ge 2Sb 2Te 5
Phase separation
X-ray photoelectron spectroscopy
Issue Date: 1-Jun-2012
Citation: Zhang, Z., Pan, J., Fang, L.W.-W., Yeo, Y.-C., Foo, Y.L., Zhao, R., Shi, L., Tok, E.S. (2012-06-01). Temperature-dependent phase separation during annealing of Ge 2Sb 2Te 5 thin films in vacuum. Applied Surface Science 258 (16) : 6075-6079. ScholarBank@NUS Repository. https://doi.org/10.1016/j.apsusc.2012.03.005
Abstract: Thermal stability of 100 nm Ge 2Sb 2Te 5 thin film during annealing from room temperature to 240°C inside a UHV chamber was studied in situ by X-ray photoelectron spectroscopy (XPS) and ex situ by X-ray diffraction (XRD) and atomic force microscopy (AFM). Ge species are found to diffuse preferentially to the surface when GST film is annealed from 25°C to 100°C. This process is accompanied by a change of phase whereby the amorphous film completely becomes face-center-cubic (FCC) phase at 100°C. From 100°C to 200°C, both Sb and Te species are observed to diffuse more to the surface. The FCC phase is partially changed into hexagonal-close-pack (HCP) phase at 200°C. At 220°C, FCC phase is completely transformed into HCP phase. Loss of Sb and Te are also detected from the surface and this is attributed to desorption due to their high vapor pressures. At 240°C, Sb and Te species are found to have desorbed completely from the surface, and leave behind Ge-rich 3D droplets on the surface. The separation of Ge 2Sb 2Te 5 into Sb,Te-rich phase and Ge-rich phase is thus the main mechanism to account for the failure of Ge 2Sb 2Te 5-based phase change memory devices under thermal stress. © 2012 Elsevier B.V. All rights reserved.
Source Title: Applied Surface Science
URI: http://scholarbank.nus.edu.sg/handle/10635/83153
ISSN: 01694332
DOI: 10.1016/j.apsusc.2012.03.005
Appears in Collections:Staff Publications

Show full item record
Files in This Item:
There are no files associated with this item.

SCOPUSTM   
Citations

12
checked on Dec 5, 2018

WEB OF SCIENCETM
Citations

12
checked on Nov 27, 2018

Page view(s)

44
checked on Oct 5, 2018

Google ScholarTM

Check

Altmetric


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.