Atomic-scale quantification of interdiffusion and dopant localization in GeSbTe-based memory devices
Fabrication of phase-change memory devices at modest or ambient temperatures leads to nanoscale compositional variations in phase-transition layers, where amorphous-polycrystalline phase change takes place via electrical switching, and can alter the device's performances. Here, by transmission...
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Veröffentlicht in: | Applied physics letters 2016-09, Vol.109 (11) |
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Sprache: | eng |
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Zusammenfassung: | Fabrication of phase-change memory devices at modest or ambient temperatures leads to nanoscale compositional variations in phase-transition layers, where amorphous-polycrystalline phase change takes place via electrical switching, and can alter the device's performances. Here, by transmission electron microscopy and atom probe tomography, we address that thermal annealing at 400 °C for 20 min induces an elemental interdiffusion in the devices consisting of TiN (top electrode), carbon-doped GeSbTe (phase-transition layer), and TiSiN (bottom heater). With respect to the employed annealing process, the Ge atoms of GeSbTe layer have diffused into TiSiN layer at a given sample volume, while the Ti atoms of TiSiN layer into GeSbTe layer. Furthermore, non-random nature of dopant distribution in the GeSbTe materials leads to a Ti-localization including dopants at the GeSbTe/TiSiN interfaces. Our findings have two important implications: First, the annealing-driven interdiffusion of Ge and Ti is a predominant mechanism responsible for nanoscale compositional variations in GeSbTe layer; second, such an interdiffusion and the resultant dopant localization play a crucial role on the driving force for amorphous-polycrystalline transition of GeSbTe-based memory devices. |
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ISSN: | 0003-6951 1077-3118 |
DOI: | 10.1063/1.4962807 |