Table salt found to boost data storage density

Researchers in Singapore say they've found a way to use common table salt to increase by 5.3 times the density at which bits of data can be stored on a hard disk drive platter.

The researchers said that the process they discovered will support densities ranging from 1.9 terabits per inch to 3.3Tbit/in., or six times what a Seagate 4TB hard drive is capable of today, which is 625Gbit/in. Given that today's hard drives can come with as much as 4TB of capacity, theoretically, the new technology would make it possible for more than 21TB of data to reside on a single drive.

The secret lies in the use of an extremely high-resolution e-beam lithography, which is the process by which fine nano-scale circuitry is created.

By adding sodium chloride (salt) to a developer solution used in lithography processes, the researchers were able to produce highly defined nanostructures that were as small as 4.5 nanometers, without the need for expensive equipment upgrades.

A nanometer is one-billionth of a meter. Today's NAND flash-based solid-state drives use lithography processes that create circuitry about 25nm in width; a human hair is 3,000 times thicker than 25nm.
The researchers' "salty developer solution" method was invented by Joel Yang, a scientist at the Institute of Materials Research and Engineering (IMRE) at Singapore's Agency for Science, Technology and Research. Yang first developed the method when he was a graduate student at MIT. Yang and researchers from the National University of Singapore and the Data Storage Institute, perfected the nanopatterning technique.

In the simplest of terms, nanopatterning more closely packs miniature structures that hold information in the form of bits. "What we have shown is that bits can be patterned more densely together by reducing the number of processing steps," Yang said in a statement. Scientists use the term "grain" to describe the packages of bits deposited on the surface of a platter.

Current technology uses tiny grains, about 7nm or 8mn in size, deposited on the surface of storage media, Yang said. However, a single bit of data is stored in a cluster of these "grains" and not in any single "grain." The researchers' bits are about 10nm in size but store information in a single structure. The researchers are now working to increase the storage density even further.

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