Tapping Probe and Organic Films Could Store Data by the Terabit

Imagine having all of the information recorded on a stack of 1,540 CDs on a disk the size of a single CD.

Or visualize having all of the information recorded on a stack of 154 CDs written on a one-inch square chip.

New probe microscopy techniques and new organic materials could be combined in the next generation data storage technology ? which will be nanometer-scale technology with probable major impact on related storage technologies, University of Arizona optical scientists say.

With $2 million in government and corporate funding, UA Optical Data Storage Center director Dror Sarid, UA optical scientist Ghassan E. Jabbour and their colleagues are pioneering theory and experiments leading to very fast, low-cost and compact memory devices.

Sarid and Jabbour believe that nanotech organic films will be the data storage medium of the near future, using micro-electro-mechanical-systems, or MEMS probe devices, to read and write on that medium. Information will be written, read and stored in clusters of molecules within the inexpensive films.

By current conventional technology, a CD (optical disk drive) holds 500 megabits of data per square inch. And by current conventional technology, a hard disk drive holds 32.6 gigabits of information per square inch, Sarid noted. (A gigabit is one billion bits of computer memory or data storage capacity.)

Industry’s specifically targeted goal is one terabit per square inch, or about one thousand gigabits per square inch of storage capacity. Conventional storage technology, at best, falls 10 times short of that goal. “There is no way you can obtain this storage density unless you develop nanotechnology,” Sarid said.

“Although conventional data storage can contain a huge amount of information, it has two problems,” Sarid said. “One, because it is mechanical, you have to wait several milliseconds to retrieve what you wrote. I mean, really, you can blink during the time it takes the system to read the disk. That’s one bottleneck.”

“And, two, while there are other ‘random access memory’ or RAM, technologies that can be read a thousand times faster than data on a hard disk, they cost 10 times more than hard-disk storage. High cost storage capacity has limited RAM technology use.”

The UA scientists are developing an idea that originated with IBM and Stanford University researchers. It combines the affordability of hard-disk storage technology and RAM technology.

The UA team has demonstrated their version of a MEMS probe that delivers pulses of electric current as the probe tip “taps” on a surface. The cantilever’s injected current changes the electrical resistance at the point it contacts the surface, which is the “writing” that can be stored and read back latter.

Sarid, Jabbour and their UA colleagues are the first (and so far the only) scientists to get positive preliminary results by using the injection of pulses with tapping probe storage. They reported the results a year ago in Applied Physics Letters and in Physical Review Letters. Science magazine highlighted the achievement in its “Editor’s Choice” section a few months later.

“In principle, one should have no trouble in making a million cantilevers operate in parallel in the MEMS probe,” Sarid said, “After all, Pentium processors in computers have millions of transistors, and this is much simpler than a transistor. And Jabbour has the expertise to fabricate nano-thick organic thin films for low-cost memory.”

Carnegie Mellon University, IBM, Hewlett-Packard and other organizations are currently pursuing alternative approaches, as the field of probe data storage is heating up, Sarid noted.

The UA Office of the Vice President for Research is among those funding the probe data storage project. Other research sponsors are keenly interested in supporting the Arizona scientists’ further work . If probe data storage is a viable technology, it may prove to be a disruptive technology, Sarid said. A “disruptive” technology so outperforms conventional technology that it quickly makes conventional technology obsolete.

Peer interest ? another sign that research concerns a scientifically hot topic ? has kept Sarid busy on the lecture circuit during the past year. Still to come are his invited talks for an international probe storage workshop convening Nov. 7 ? 8 at Carnegie Mellon University, a National Science Foundation-funded conference on micro and nano technologies for sensing Dec. 12 ? 14 in Melbourne, Australia, and a Jan. 6 – 8 data storage conference in Monterey, Calif.

Sarid recently was named one of two university advisors for the Information Storage Industry Consortium (INSIC), a consortium of more than 50 corporations, universities and government organizations working to develop advanced data storage technologies.

Jabbour chairs the International Society for Optical Engineering’s annual meeting track for nanotechnology, and he is editor of two forthcoming books on nanotechnology.

Sarid, Jabbour and their research associates Brendan McCarthy and Tony Peterson have written a chapter on “Nanotechnology for Data Storage Applications” for a forthcoming Springer-Verlag book on nanotechnology.