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Surface etching mechanism of carbon-doped Ge2Sb2Te5 phase change material in fluorocarbon plasma

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Abstract

Recently, carbon-doped Ge2Sb2Te5 (CGST) phase change material has been widely researched for being highly promising material for future phase change memory application. In this paper, the reactive-ion etching of CGST film in CF4/Ar plasma is studied. Compared with GST, the etch rate of CGST is relatively lower due to the existence of carbon which reduce the concentration of F or CF x reactive radicals. It was found that Argon plays an important role in defining the sidewall edge acuity. Compared with GST, more physical bombardment is required to obtain vertical sidewall of CGST. The effect of fluorocarbon gas on the damage of the etched CGST film was also investigated. A Ge- and Sb-deficient layer with tens of nanometers was observed by TEM combining with XPS analysis. The reaction between fluorocarbon plasma and CGST is mainly dominated by the diffusion and consumption of reactive fluorine radicals through the fluorocarbon layer into the CGST substrate material. The formation of damage layer is mainly caused by strong chemical reactivity, low volatility of reaction compounds and weak ion bombardment.

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Acknowledgments

This work was supported by the “Strategic Priority Research Program” of the Chinese Academy of Sciences (XDA09020402), National Integrate Circuit Research Program of China (2009ZX02023-003), National Natural Science Foundation of China (61261160500, 61376006, 61401444, 61504157), Science and Technology Council of Shanghai (13ZR1447200, 14DZ2294900, 14ZR1447500, 15DZ2270900).

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Authors and Affiliations

  1. State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Micro-system and Information Technology, Chinese Academy of Sciences, Shanghai, 200050, China

    Lanlan Shen, Sannian Song, Zhitang Song, Le Li, Tianqi Guo, Yan Cheng, Shilong Lv, Liangcai Wu, Bo Liu & Songlin Feng

  2. Graduate School of the Chinese Academy of Sciences, Beijing, 100049, China

    Lanlan Shen

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  1. Lanlan Shen
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Correspondence to Lanlan Shen.

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Shen, L., Song, S., Song, Z. et al. Surface etching mechanism of carbon-doped Ge2Sb2Te5 phase change material in fluorocarbon plasma. Appl. Phys. A 122, 865 (2016). https://doi.org/10.1007/s00339-016-0381-4

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