Energy-Efficient Phase-Change Memory with Graphene as Thermal Barrier

Ahn, C., Fong, S., Kim, Y., Lee, S., Sood, A., Neumann, C., Asheghi, M., Goodson, K.E., Pop, E., Wong, H.S.P., 2015, "Energy-Efficient Phase-Change Memory with Graphene as Thermal Barrier," Nano Letters, DOI: 10.1021/acs.nanolett.5b02661

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Phase-change memory (PCM) is an important class of data storage, yet lowering the programming current of individual devices is known to be a significant challenge. Here we improve the energy-efficiency of PCM by placing a graphene layer at the interface between the phase-change material, Ge2Sb2Te5 (GST), and the bottom electrode (W) heater. Graphene-PCM (G-PCM) devices have ∼40% lower RESET current compared to control devices without the graphene. This is attributed to the graphene as an added interfacial thermal resistance which helps confine the generated heat inside the active PCM volume. The G-PCM achieves programming up to 10^5 cycles, and the graphene could further enhance the PCM endurance by limiting atomic migration or material segregation at the bottom electrode interface.

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Phase change memory (PCM or PCRAM) is based on rapid, thermally-induced phase transitions in Ge2Sb2Te5 (GST) and related compounds. Because the phase change is induced by temperature changes, thermal...