Microstructure-dependent DC set switching behaviors of Ge-Sb-Te-based phase-change random access memory devices accessed by in situ TEM
SCIE
SCOPUS
- Title
- Microstructure-dependent DC set switching behaviors of Ge-Sb-Te-based phase-change random access memory devices accessed by in situ TEM
- Authors
- Baek, K; Song, K; Son, SK; Oh, JW; Jeon, SJ; Kim, W; Kim, HJ; Oh, SH
- Date Issued
- 2015-06
- Publisher
- Nature Publishing Group
- Abstract
- Phase-change random access memory (PCRAM) is one of the most promising nonvolatile memory devices. However, inability to secure consistent and reliable switching operations in nanometer-scale programing volumes limits its practical use for highdensity applications. Here, we report in situ transmission electron microscopy investigation of the DC set switching of Ge-Sb-Te (GST)-based vertical PCRAM cells. We demonstrate that the microstructure of GST, particularly the passive component surrounding the dome-shaped active switching volume, plays a critical role in determining the local temperature distribution and is therefore responsible for inconsistent cell-to-cell switching behaviors. As demonstrated by a PCRAM cell with a highly crystallized GST matrix, the excessive Joule heat can cause melting and evaporation of the switching volume, resulting in device failure. The failure occurred via two-step void formation due to accelerated phase separation in the molten GST by the polaritydependent atomic migration of constituent elements. The presented real-time observations contribute to the understanding of inconsistent switching and premature failure of GST-based PCRAM cells and can guide future design of reliable PCRAM.
- URI
- https://oasis.postech.ac.kr/handle/2014.oak/35547
- DOI
- 10.1038/AM.2015.49
- ISSN
- 1884-4049
- Article Type
- Article
- Citation
- NPG Asia Materials, vol. 7, 2015-06
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