Embedded Magnetic
Memory (MRAM)
Goal
Develop ultra-low-power magnetic memory for embedded and reconfigurable computing systems for spacecraft. Based on Prof. Yang-Ki Hong's patent-pending PacMan magnetic element.
Sponsor
Dr.
Jim Lyke, Air Force Research Laboratory, Space Electronic (AFRL/VSSE)
Research Team
Dr.
Gregory Donohoe, University of Idaho, Principal Investigator
Dr.
Yang-Ki Hong, University
of Idaho, Co-Investigator, Materials
Mr.
Joe Hass, University of Idaho/CAMBR,
Lead engineer, circuits
Dr.
Jim Murguia, Solid State
Scientific, Inc., Process integration
Mr.
Doug Hackler, American Semiconductor,
Inc., Boise, ID. Fabrication and test
Papers Published
under the MRAM Project
Download MRAM-II Final Report (PDF)
The PacMan Shape
The key to writing a Magnetic Tunneling Junction memory cell is to induce the "free" magnetic layer to change magnetic polarity by running a current pulse through a nearby metal conductor and creating an electromagnetic switching field. This magnetic element should have the following properties:
- Fast switching speed
- Low switching energy
- Repeatabilty - it should switch every time without fail
- Selectivity - the switching field should cause the
intended cell to switch, and no other
These properties are established by the material composition and the shape of the magnetic element. Prof. Hong and his team have arrived at an optimal combination, based on the Pac Man shape. The picture at right shows a PacMan magnetic element fabricated in Prof. Hong's lab.
Fabricated Magnetic
Tunneling Junction Memory Cells
4 x 4 array of test cells; inset shows an individual cell