The Transactions of the Korean Institute of Electrical Engineers C (대한전기학회논문지:전기물성ㆍ응용부문C)

The Korean Institute of Electrical Engineers (대한전기학회)
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The Characteristics of Chalcogenide $Ge_1Se_1Te_2$ Thin Film for Nonvolatile Phase Change Memory Device

비휘발성 상변화메모리소자에 응용을 위한 칼코게나이드 $Ge_1Se_1Te_2$ 박막의 특성

  • Published : 2006.06.01
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Abstract

In the present work, we investigate the characteristics of new composition material, chalcogenide $Ge_1Se_1Te_2$ material in order to overcome the problems of conventional PRAM devices. The Tc of $Ge_1Se_1Te_2$ bulk was measured $231.503^{\circ}C$ with DSC analysis. For static DC test mode, at low voltage, two different resistances are observed. depending on the crystalline state of the phase-change resistor. In the first sweep, the as-deposited amorphous $Ge_1Se_1Te_2$ showed very high resistance. However when it reached the threshold voltage(about 11.8 V), the electrical resistance of device was drastically reduced through the formation of an electrically conducting path. The phase transition between the low conductive amorphous state and the high conductive crystal]me state was caused by the set and reset pulses respectively which fed through electrical signal. Set pulse has 4.3 V. 200 ns. then sample resistance is $80\sim100{\Omega}$. Reset pulse has 8.6 V 80 ns, then the sample resistance is $50{\sim}100K{\Omega}$. For such high resistance ratio of $R_{reset}/R_{set}$, we can expect high sensing margin reading the recorded data. We have confirmed that phase change properties of $Ge_1Se_1Te_2$ materials are closely related with the structure through the experiment of self-heating layers.

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References

  1. S. R. Ovshinsky,'Reversible Electrical Switching Phenomena in Disordered Structures' Phys. Rev. Letters, Vol. 21, p. 1450, 1968 https://doi.org/10.1103/PhysRevLett.21.1450
  2. David Adler 'Switching Phenomena in Thin Film', J. Vac. Sci. Technol. 10, p .728, 1973 https://doi.org/10.1116/1.1318423
  3. H. B. Chung, C. Y. Park, 'Electrical Characteristics of the Thin Film Interface of Amorphous Chalcogenide Semiconductor.', KIEE, Vol. 29 No. 2 p. 37, 1980
  4. Hong-Bay Chung, 'Transition Characteristics of ON-OFF State of Amorphous Chalcogenide Semiconductor', J, of Kwangwoon Univ, Vol. 9, p. 59, 1980
  5. N. Yamada, E. Ohno, K. Nishiuchi, N. Akahira, M. Takao, 'Rapid-phase transitions of GeTe-$Sb_2Te_3$ pseudo-binary amorphous thin films for an optical disk memory.', J. Appl, Phys., Vol. 69 No. 5, p. 2849, 1991 https://doi.org/10.1063/1.348620
  6. G. Wicker,' Nonvolatile, high density, high performance phase change memory.', SPIE vol. 3891 p. 2, Oct. 1999 https://doi.org/10.1117/12.364449
  7. Ron Neale, 'Amorphous non-volatile memory : the past and the future', Electronic Engineering April 2001
  8. H. Horii et al. 'Novel cell structure of PRAM with thin metal layer inserted GeSbTe'. IEDM Tech. Dig. p. 901, 2003 https://doi.org/10.1109/IEDM.2003.1269424
  9. S. J. Yang, K. Shin, J. I. Park, K. N. Lee, H. B. Chung,'The Study of Phase-change with Temperature and Electrical Field in Chalcogenide Thin Film', Trans. on EEM, Vol. 4, No. 5, p. 24, 2003 https://doi.org/10.4313/TEEM.2003.4.5.024
  10. S. J. Yang, J. M. Lee, K. Shin, H. B. Chung, 'The Phase Transition with Electric Field in Ternary Chalcogenide Thin Films' Trans. on MME, Vol .5, No. 5, p. 185, 2004 https://doi.org/10.4313/TEEM.2004.5.5.185
  11. J. M. Lee, S. J. Yang, K. Shin, H. B. Chung, 'The Study on the Characteristic of Phase Transition ill Difference Thickness of $Se_1Sb_2Te_2$ Thin Film' Trans. on MME, Vol. 5, No. 6, p. 241, 2004 https://doi.org/10.4313/TEEM.2004.5.6.241