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A Study On Properties and Phase Change Characteristics of (GeTe)x(Sb2Te3) (x=0.5, 1, 2, 8) Thin Films for PRAM

PRAM을 위한 (GeTe)x(Sb2Te3) (x=0.5, 1, 2, 8) 박막의 물성 및 상변환 특성 연구

  • 김성원 (전남대학교 대학원 신화학소재공학과) ;
  • 송기호 (전남대학교 대학원 신화학소재공학과) ;
  • 이현용 (전남대학교 응용화학공학부 촉매연구소)
  • Published : 2008.07.01

Abstract

In this work, we report several experimental data capable of evaluating the phase transformation characteristics of GeSbTe pseudobinary thin films comprehensively utilized as phase change materials. The phase transformation of the GeSbTe thin films was confirmed by XRD measurement from amorphous to hexagonal structure via fee structure except for $Ge_8Sb_2Te_{11}$. In addition, X-ray photoelectron spectra analysis revealed to weaken Ge-Te bond for $Ge_2Sb_2Te_5$ and to strengthen the bonds of all elements for $Ge_8Sb_2Te_{11}$ during the amorphous to crystalline transition. The values of optical energy gap $(E_{OP})$ were around 0.71 and 0.50 eV and the slopes of absorption in extended region (B) were ${\sim}5.1{\times}10^5$ and ${\sim}10{\times}10^5cm^{-1}{\cdot}V^{-1}$ for the amorphous and fcc-crystalline structures, respectively. Finally, the kinetics of amorphous-to-crystalline phase change on the GeSbTe films was characterized using a nano-pulse scanner with 658-nm laser diode (power; $1{\sim}17$ mW, pulse duration; $10{\sim}460$ ns).

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