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http://dx.doi.org/10.4313/JKEM.2019.32.5.376

Characteristics of Cu-Doped Ge8Sb2Te11 Thin Films for PRAM  

Kim, Yeong-Mi (Department of Advanced Chemicals and Engineering, Chonnam National University)
Kong, Heon (Department of Advanced Chemicals and Engineering, Chonnam National University)
Kim, Byung-Cheul (Department of Electronic Engineering, Gyeongnam National University of Science and Technology)
Lee, Hyun-Yong (School of Chemical Engineering, Chonnam National University)
Publication Information
Journal of the Korean Institute of Electrical and Electronic Material Engineers / v.32, no.5, 2019 , pp. 376-381 More about this Journal
Abstract
In this work, we evaluated the structural, electrical and optical properties of $Ge_8Sb_2Te_{11}$ and Cu-doped $Ge_8Sb_2Te_{11}$ thin films prepared by rf-magnetron reactive sputtering. The 200-nm-thick deposited films were annealed in a range of $100{\sim}400^{\circ}C$ using a furnace in an $N_2$ atmosphere. The amorphous-to-crystalline phase changes of the thin films were investigated by X-ray diffraction (XRD), UV-Vis-IR spectrophotometry, a 4-point probe, and a source meter. A one-step phase transformation from amorphous to face-centered-cubic (fcc) and an increase of the crystallization temperature ($T_c$) was observed in the Cu-doped film, which indicates an enhanced thermal stability in the amorphous state. The difference in the optical energy band gap ($E_{op}$) between the amorphous and crystalline phases was relatively large, approximately 0.38~0.41 eV, which is beneficial for reducing the noise in the memory devices. The sheet resistance($R_s$) of the amorphous phase in the Cu-doped film was about 1.5 orders larger than that in undoped film. A large $R_s$ in the amorphous phase will reduce the programming current in the memory device. An increase of threshold voltage ($V_{th}$) was seen in the Cu-doped film, which implied a high thermal efficiency. This suggests that the Cu-doped $Ge_8Sb_2Te_{11}$ thin film is a good candidate for PRAM.
Keywords
PRAM; Chalcogenide; Sputtering; Thermal stability;
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1 S. R. Ovshinsky, Phys. Rev. Lett., 21, 1450 (1968). [DOI:https://doi.org/10.1103/PhysRevLett.21.1450]   DOI
2 C. J. Park, H. Kong, H. Y. Lee, and J. B. Yeo, J. Korean Phys. Soc., 71, 42 (2017). [DOI: https://doi.org/10.3938/jkps.71.42]   DOI
3 N. Yamada, E. Ohno, K. Nishiuchi, N. Akahira, and M. Takao, J. Appl. Phys., 69, 2849 (1991). [DOI: https://doi.org/10.1063/1.348620]   DOI
4 M. Zhu, M. Xia, F. Rao, X. Li, L. Wu, X. Ji, S. Lv, Z. Song, S. Feng, H. Sun, and S. Zhang, Nat. Commun., 5, 4086 (2014). [DOI: https://doi.org/10.1038/ncomms5086]   DOI
5 K. H. Song, S. C. Baek, and H. Y. Lee, J. Korean Phys. Soc., 61, 10 (2012). [DOI: https://doi.org/10.3938/jkps.61.10]   DOI
6 K. Ding, K. Ren, F. Rao, Z. Song, L. Wu, B. Liu, and S. Feng, Mater. Lett., 125, 143 (2014). [DOI: https://doi.org/10.1016/j.matlet.2014.03.180]   DOI
7 S. Kumar, D. Singh, and R. Thangaraj, Thin Solid Films, 531, 577 (2013). [DOI: https://doi.org/10.1016/j.tsf.2013.01.057]   DOI
8 A. Pirovano, A. L. Lacaita, A. Benvenuti, F. Pellizzer, and R. Bez, IEEE Trans. Electron Devices, 51, 452 (2004). [DOI: https://doi.org/10.1109/TED.2003.823243]   DOI
9 Y. Utsugi and Y. Mizushima, J. Appl. Phys., 51, 1773 (1980). [DOI:https://doi.org/10.1063/1.327738]   DOI
10 J. Kalb, F. Spaepen, and M. Wutting, Appl. Phys. Lett., 84, 5240 (2004). [DOI: https://doi.org/10.1063/1.1764591]   DOI
11 K. H. Song, S. W. Kim, J. H. Seo, and H. Y. Lee, Thin Solid Films, 517, 3958 (2009). [DOI: https://doi.org/10.1016/j.tsf.2009.01.128]   DOI
12 M. E. Fine and N. Hsieh, J. Am. Ceram. Soc., 57, 502 (1974). [DOI:https://doi.org/10.1111/j.1151-2916.1974.tb11407.x]
13 K. H. Song, J. H. Seo, J. H. Kim, and H. Y. Lee, J. Appl. Phys., 106, 123529 (2009). [DOI: https://doi.org/10.1063/1.3273400]   DOI
14 J. L. Xia, B. Liu, Z. T. Song, S. L. Feng, and B. Chen, Chin. Phys. Lett., 22, 934 (2005). [DOI: https://doi.org/10.1088/0256-307X/22/4/043]   DOI
15 A. Pirovano, A. L. Lacaita, F. Pellizzer, S. A. Kostylev, A. Benvenuti, and R. Bez, IEEE Trans. Electron Devices, 51 714 (2002). [DOI: https://doi.org/10.1109/TED.2004.825805]
16 J. H. Yi, Y. H. Ha, J. H. Park, B. J. Kuh, H. Horii, Y. T. Kim, S. O. Park, Y. N. Hwang, S. H. Lee, S. J. Ahn, S. Y. Lee, J. S. Hong, K. H. Lee, N. I. Lee, H. K. Kang, U. I. Chung, and J. T. Moon, Proc. IEEE International Electron Devices Meeting 2003 (IEEE, Washington, USA, 2003) p. 901. [DOI: https://doi.org/10.1109/IEDM.2003.1269424]
17 A. Pirovano, A. L. Lacaita, D. Merlani, A. Benvenuti, F. Pellizzer, and R. Bez, Digest. International Electron Devices Meeting (IEEE, San Francisco, USA, 2002) p. 923. [DOI:https://doi.org/10.1109/IEDM.2002.1175987]