BROWSE
Detail
Journal Article
Bilayer Heater Electrode for Improving Reliability of Phase-Change Memory Devices
- Issue Date
- 2008-03
- Citation
- Journal of the Electrochemical Society, v.115 no.5, pp.H314-H318
- ISSN
- 0013-4651
- Publisher
- Electrochemical Society (ECS)
- Language
- English
- Type
- Journal Article
- Abstract
- This work reports the effect of the heater electrode of a bilayer structure on phase-change memory (PCM) devices. The large amount of Joule heat generated from the high-resistive single-layer heater degraded the PCM device, whereas the bilayer heater composed of two kinds of different materials improved the device reliability. The PCM device employing a 2.0 m cm SiGe heater in contact with a GeSbTe phase-change material exhibited a much smaller programming current than that employing a conventional 0.5 m cm TiN heater. However, the open-mode failure, where the cell resistance was stuck at a high value, frequently occurred in the PCM device with the SiGe heater. Transmission electron microscopy revealed that the open-mode failure resulted from the physical separation of the upper tungsten electrode from the GeSbTe layer. The reliability problem was completely removed by inserting a 0.1 m cm TiN layer between the GeSbTe and SiGe layers. In addition, we found that the TiN layer in a GeSbTe/TiN/SiGe multilayer structure prevented the diffusion of Si and Ge atoms originating from the SiGe layer. The improved reliability with the bilayer heater is attributed to the moderate temperature rise in the GeSbTe layer preserving the attachment of the tungsten electrode to the GeSbTe layer. © 2008 The Electrochemical Society.
- KSP Keywords
- Bilayer structure, Cell resistance, Device reliability, Different materials, Moderate temperature, Phase Change Material(PCM), Single-layer, Temperature Rise, TiN layer, Transmission Electron Microscopy(TEM), Tungsten electrode