Materials Breakthrough Could Eliminate Bootups
by Linda Dailey Paulson
Researchers have developed an approach using a ferroelectric material that could enable computers to start working immediately upon being powered up, without time-consuming bootups. The technique, which could be used in computer memory and transistors, could also prevent data losses that power outages cause.
The research involved collaboration among scientists from Cornell University, Northwestern University, Pennsylvania State University, and the University of Pittsburgh, with participation from organizations such as Intel, Motorola, the US National Institute of Standards and Technology, and the US Department of Energy's Ames Laboratory, said Cornell professor Darrell Schlom, a project participant.
To create binary data's ones and zeros, the researchers' system applies a small electric field to change the electric charge of various bits within the ferroelectric material they used. This polarization would remain after users shut off the electricity, enabling persistent storage. Conventional RAM loses stored data when the power is turned off.
The scientists are also working on ways to use their technique to develop transistors that maintain state, said University of Pittsburgh professor Jeremy Levy, a project participant.
With both transistors and memory that retain their state when turned off, a machine could begin computation again as soon as it powers up, without a bootup process, he noted.
The problem of creating a ferroelectric material that would work in computers this way has baffled researchers for more than 50 years.
The scientists who achieved the breakthrough worked with the ferroelectric materials related to lead zirconium titanate and strontium bismuth tantalite, which are found in smart cards like those used in subway passes.
According to Levy, they worked with an oxide, strontium titanate, that is almost but not quite ferroelectric. Researchers' previous attempts to use already-ferroelectric oxides in this process had been unsuccessful, according to Schlom.
The strontium titanate squeezes its atoms to match the spacing of the atoms in the single crystal of silicon on which the material is grown, explained Schlom. The strain and heat created by the squeezing process makes the strontium titanate material ferroelectric. See image to the right.
The research was the first in this area to put a ferroelectric material in direct contact with the silicon, without intervening layers. The materials must be in direct contact for the proper electrical activity to occur.
The approach also didn't cause a thermal/kinetic reaction between the two substances that would create a new layer of intervening material, said Levy.
The scientists accomplished this by using a Motorola-developed low-temperature, low-oxygen pressure process that slowed chemical reactions.
More research in areas such as fabrication and testing is needed, according to Schlom. And the scientists eventually will have to make and evaluate sensors and other individual devices using the technology. They could then integrate these components into a system.
Until these challenges are solved, Schlom said, the technology can't be commercialized.
News Briefs written by Linda Dailey Paulson, a freelance technology writer based in Ventura, California. Contact her at ldpaulson@yahoo.com.
