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Study of the Structural Transformation of Ge2Sb2Te5 Induced by Current Pulse in Phase Change Memory

Published online by Cambridge University Press:  01 February 2011

Rong Zhao ,
Tow Chong Chong ,
Lu Ping Shi ,
Pik Kie Tan ,
Hao Meng ,
Xiang Hu ,
Ke Bin Li  and
An Yan Du
Rong Zhao
Affiliation:
Data Storage Institute, A*Star, Singapore117608
Tow Chong Chong
Affiliation:
Data Storage Institute, A*Star, Singapore117608
Lu Ping Shi
Affiliation:
Data Storage Institute, A*Star, Singapore117608
Pik Kie Tan
Affiliation:
Data Storage Institute, A*Star, Singapore117608
Hao Meng
Affiliation:
Department of Electrical & Computer Engineering, University of Minnesota, MN 55455, USA
Xiang Hu
Affiliation:
Data Storage Institute, A*Star, Singapore117608
Ke Bin Li
Affiliation:
Data Storage Institute, A*Star, Singapore117608
An Yan Du
Affiliation:
Institute of Microelectronics, A*Star, Singapore117685
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Abstract

The electrical induced structural transformation of Ge2Sb2Te5 thin film in phase change memory device was investigated using micro-Raman spectroscopy and transmission electronic microscopy (TEM). Selected area electron diffraction (SAD) pattern showed that the electrical-induced Ge2Sb2Te5 film was crystallized into a face-centered cubic structure. Micro-Raman spectra show that the Ge2Sb2Te5 active layer at the high resistance state exhibited two minor peaks superposed on the broad peak after several switch cycles, which is identical to those of the Ge2Sb2Te5 active layer at the low resistance state. This is most likely due to the accumulation of segregated crystallites. TEM results suggest that the existence of nano-sized nuclei clusters resulted in the reduced resistance for the Ge2Sb2Te5 active layer at the high resistance state after first several switches. The dependence of resistance on the cycle number indicates that the deterioration of the Ge2Sb2Te5 active layer is resulted from the incomplete amorphization process, which is consistent with the micro-Raman results.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 803: Symposia GG/HH – Advanced Characterization Techniques for Data Storage Materials – Phase Change and Nonmagnetic Materials for Data Storage , 2003 , HH1.5
Copyright
Copyright © Materials Research Society 2004

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References

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