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The Influence of Nitrogen Doping on the Chemical and Local Bonding Environment of Amorphous and Crystalline Ge2Sb2Te5

Published online by Cambridge University Press:  31 January 2011

Joseph Washington ,
Eric A. Joseph ,
Michael A. Paesler ,
Gerald Lucovsky ,
Jean L. Jordan-Sweet ,
Simone Raoux ,
Chieh-Fang Chen ,
Adam Pyzyna ,
Ravi K. Dasaka  and
Chung H. Lam
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Joseph Washington
Affiliation:
jswashin@ncsu.edu, North Carolina State University, Physics, Raleigh, North Carolina, United States
Eric A. Joseph
Affiliation:
ejoseph@us.ibm.com, T. J. Watson Research Center, IBM/Macronix PCRAM Joint Project, Yorktown Heights, New York, United States
Michael A. Paesler
Affiliation:
paesler@ncsu.edu, North Carolina State University, Physics, Raleigh, North Carolina, United States
Gerald Lucovsky
Affiliation:
lucovsky@ncsu.edu, North Carolina State University, Physics, Raleigh, North Carolina, United States
Jean L. Jordan-Sweet
Affiliation:
jljs@us.ibm.com, IBM T.J. Watson Research Center, Yorktown Heights, New York, United States
Simone Raoux
Affiliation:
simone_raoux@almaden.ibm.com, IBM Almaden Research Center, San Jose, California, United States
Chieh-Fang Chen
Affiliation:
chencf@us.ibm.com, T. J. Watson Research Center, IBM/Macronix PCRAM Joint Project, Yorktown Heights, New York, United States
Adam Pyzyna
Affiliation:
pyzyna@us.ibm.com, T. J. Watson Research Center, IBM/Macronix PCRAM Joint Project, Yorktown Heights, New York, United States
Ravi K. Dasaka
Affiliation:
rkdasaka@us.ibm.com, IBM T.J. Watson Research Center, Yorktown Heights, New York, United States
Chung H. Lam
Affiliation:
schrott@us.ibm.com, T. J. Watson Research Center, IBM/Macronix PCRAM Joint Project, Yorktown Heights, New York, United States
Alejandro Schrott
Affiliation:
clam@us.ibm.com, T. J. Watson Research Center, IBM/Macronix PCRAM Joint Project, Yorktown Heights, New York, United States
Joseph C. Woicik
Affiliation:
bravel@bnl.gov, National Institute of Standards and Technology, Synchrotron Methods Group, Upton, New York, United States
Bruce Ravel
Affiliation:
woicik@bnl.gov, 2National Institute of Standards and Technology, Gaithersburg, Maryland, United States
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Abstract

Recent interest in phase change materials (PCMs) for non-volatile memory applications has been fueled by the promise of scalability beyond the limit of conventional DRAM and NAND flash memory [1]. However, for such solid state device applications, Ge2Sb2Te5 (GST), GeSb, and other chalcogenide PCMs require doping. Doping favorably modifies crystallization speed, crystallization temperature, and thermal stability but the chemical role of the dopant is not yet fully understood. In this work, X-ray Absorption Fine Spectroscopy (XAFS) is used to examine the chemical and structural role of nitrogen doping (N-) in as-deposited and crystalline GST thin films. The study focuses on the chemical and local bonding environment around each of the elements in the sample, in pre and post-anneal states, and at various doping concentrations. We conclude that the nitrogen dopant forms stable Ge-N bonds as deposited, which is distinct from GST bonds, and remain at the grain boundary of the crystallites such that the annealed film is comprised of crystallites with a dopant rich grain boundary.

Keywords

extended x-ray absorption fine structure(EXAFS)amorphousdopant
Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 1160: Symposium H – Materials and Physics for Nonvolatile Memories , 2009 , 1160-H13-08
Copyright
Copyright © Materials Research Society 2009

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