Available Technologies

Browse Penn-owned technologies available for licensing.

Nanowire phase change memory


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: 


Intellectual Property: 

United States Patent 8,759,810

Reference Media: 

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)

Desired Partnerships: 

  • License
  • Sponsored Research  

Patent Information:


Docket # W5329

For Information, Contact:

Qishui Chen Licensing Officer, SEAS/SAS Licensing Group
University of Pennsylvania