中国物理B ›› 2004, Vol. 13 ›› Issue (11): 1947-1950.doi: 10.1088/1009-1963/13/11/033

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Raman spectra and XPS studies of phase changes in Ge2Sb2Te5 films

刘波1, 宋志棠1, 张挺1, 封松林1, Chen Bomy2   

  1. (1)Research Centre of Functional Semiconductor Film Engineering Technology, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; (2)Silicon Storage Technology, Inc., 1171 Sonora Court, Sunnyvale, CA 94086, USA
  • 收稿日期:2004-04-14 修回日期:2004-05-27 出版日期:2004-11-20 发布日期:2005-06-20
  • 基金资助:
    Project supported by the National High Technology Development Programme of China (Grant No 2003AA302720), Shanghai Nanotechnology Promotion Centre (0352nm016, 0359nm204, 0252nm084), China Postdoctoral Foundation (2003034308), K. C. Wong Education Foundati

Raman spectra and XPS studies of phase changes in Ge2Sb2Te5 films

Liu Bo (刘波)a, Song Zhi-Tang (宋志棠)a, Zhang Ting (张挺)a, Feng Song-Lin (封松林)a, Chen Bomyb   

  1. a Research Centre of Functional Semiconductor Film Engineering Technology, State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, Shanghai 200050, China; b Silicon Storage Technology, Inc., 1171 Sonora Court, Sunnyvale, CA 94086, USA
  • Received:2004-04-14 Revised:2004-05-27 Online:2004-11-20 Published:2005-06-20
  • Supported by:
    Project supported by the National High Technology Development Programme of China (Grant No 2003AA302720), Shanghai Nanotechnology Promotion Centre (0352nm016, 0359nm204, 0252nm084), China Postdoctoral Foundation (2003034308), K. C. Wong Education Foundati

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摘要： Ge_2Sb_2Te_5 film was deposited by RF magnetron sputtering on Si (100) substrate. The structure of amorphous and crystalline Ge_2Sb_2Te_5 thin films was investigated using XRD, Raman spectra and XPS. XRD measurements revealed the existence of two different crystalline phases, which has a FCC structure and a hexagonal structure, respectively. The broad peak in the Raman spectra of amorphous Ge_2Sb_2Te_5 film is due to the amorphous －Te－-Te－ stretching. As the annealing temperature increases, the broad peak separates into two peaks, which indicates that the heteropolar bond in GeTe_4 and the Sb－Sb bond are connected with four Te atoms, and other units such as (TeSb) Sb－Sb (Te_2) and (Sb_2) Sb－Sb (Te_2), where some of the four Te atoms in the above formula are replaced by Sb atoms, remain in crystalline Ge_2Sb_2Te_5 thin film. And from the results of Raman spectra and XPS, higher the annealing temperature, more Te atoms bond to Ge atoms and more Sb atoms substitute Te in (Te_2) Sb－Sb (Te_2).

关键词: Ge_2Sb_2Te_5, structure, Raman spectra, XPS

Abstract: Ge$_2$Sb$_2$Te$_5$ film was deposited by RF magnetron sputtering on Si (100) substrate. The structure of amorphous and crystalline Ge$_2$Sb$_2$Te$_5$ thin films was investigated using XRD, Raman spectra and XPS. XRD measurements revealed the existence of two different crystalline phases, which has a FCC structure and a hexagonal structure, respectively. The broad peak in the Raman spectra of amorphous Ge$_2$Sb$_2$Te$_5$ film is due to the amorphous －Te－-Te－ stretching. As the annealing temperature increases, the broad peak separates into two peaks, which indicates that the heteropolar bond in GeTe$_4$ and the Sb－Sb bond are connected with four Te atoms, and other units such as (TeSb) Sb－Sb (Te$_2$) and (Sb$_2$) Sb－Sb (Te$_2$), where some of the four Te atoms in the above formula are replaced by Sb atoms, remain in crystalline Ge$_2$Sb$_2$Te$_5$ thin film. And from the results of Raman spectra and XPS, higher the annealing temperature, more Te atoms bond to Ge atoms and more Sb atoms substitute Te in (Te$_2$) Sb－Sb (Te$_2$).

Key words: Ge$_2$Sb$_2$Te$_5$, structure, Raman spectra, XPS

中图分类号:  (Infrared and Raman spectra)

  • 78.30.-j
79.60.Dp (Adsorbed layers and thin films) 78.66.Jg (Amorphous semiconductors; glasses) 81.15.Cd (Deposition by sputtering) 61.66.Fn (Inorganic compounds) 61.50.Lt (Crystal binding; cohesive energy)