Phase Change Memory (PCM) is a leading contender to replace flash memory. In PCM devices, a material is heated to undergo glass transition, changing back and forth between the amorphous and crystalline state. However, existing PCM devices have experienced problems with reliability and threshold voltage drift. In order to make commercially viable PCM devices, better solutions are required.
Researchers at the University of Pennsylvania have developed a nanowire-based PCM that shows better stress relaxation, and thus better long term reliability, than thin-film devices. The researchers discovered that stress relaxation behavior is the key cause of time-dependent drift in PCM device properties, which results in poor reliability. The design of the new PCM device uses exposed nanowires rather than conventional embedded thin films. These free-standing nanowires show much less long-term drift than thin film devices. The large surface area of the nanowires allows them to quickly and efficiently relax stress after phase change, resulting in better performance.
- Faster relaxation of residual stresses
- Better long term reliability and reduced temporal drift
Stage of Development:
United States Patent 8,759,810
Mitra, M., Jung, Y., Gianola, D. S., & Agarwal, R. (2010). Extremely low drift of resistance and threshold voltage in amporphous phase change nanowire devices. Applied Physics Letters, 96(22), 222111. (Featured graphic referenced from this paper)
- Sponsored Research
Docket # W5329