Switching at the contacts in Ge9Sb1Te5 phase-change nanowire devices
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Date
2019-04-26
Authors
Alialy, Sahar
Gabriel, Michelle
Davitt, Fionán
Holmes, Justin D.
Boland, John J.
Journal Title
Journal ISSN
Volume Title
Publisher
IOP Publishing
Published Version
Abstract
Phase-change random access memory is a promising approach to non-volatile memory. However, the inability to secure consistent, reliable switching on a nanometre scale may limit its practical use for high density applications. Here, we report on the switching behaviour of PCRAM cells comprised of single crystalline Ge9Sb1Te5 (GST) nanowires. We show that device switching is dominated by the contacts and does not result in a resistance change within the bulk of the wire. For the devices studied, the typical contact resistance was ~30 kΩ, whereas the resistance of the GST channel was 1.8 kΩ. The applied voltage was predominately dropped across the passivating oxide on the surface of the GST nanowires, resulting in local resistive switching at the contacts and local power dissipation, which limited the endurance of the devices produced. The optimal device must balance low resistance contacts with a more resistive channel, to facilitate phase change switching within the nanowires. These results highlight the importance of contact formation on the switching properties in phase change devices and help guide the future design of more reliable neuromorphic devices.
Description
Keywords
Neuromorphic , Switching , Contact resistance , Phase change , Nanowire
Citation
Alialy, S., Gabriel, M., Davitt, F., Holmes, J. D. and Boland, J. J. (2019) 'Switching at the contacts in Ge9Sb1Te5 phase-change nanowire devices', Nanotechnology. doi: 10.1088/1361-6528/ab1cf8