How to increase the data storage density of HDDs - just add salt
By Darren Quick
November 1, 2011
While Solid State Drives (SSDs) are seen as the way of the future for computer data storage and their prices have started to come down as their capacities increase, they still can't compete with traditional Hard Disk Drives (HDDs) in terms of bang for your buck. Now a team of researchers from Singapore has moved the goalposts yet again and shown traditional HDDs still have some life in them by developing a process that can increase the data recording density of HDDs to six times that of current models.
The researchers from the Institute of Materials Research and Engineering (IMRE), who worked in collaboration with the National University of Singapore (NUS) and the Data Storage Institute (DSI), liken the new process to packing a suitcase - the neater you pack, the more you can carry.
Conventional HDDs store data using randomly distributed nanoscopic magnetic grains, with a few tens of grains used to form one bit. This allows the latest model HDDs to hold up to 0.5 Terabit/in2 of information. Using nanopatterning to create uniform arrays of magnetic bits, the team was able to increase the data storage density to up to 3.3 Terabit/in2.
The secret of the new technology lies in the use of an extremely high-resolution e-beam lithography process that produces super fine nano-sized structures. Dr Joel Yang, the IMRE scientist who heads the project, found that adding sodium chloride - or table salt - to a developer solution used in existing lithography processes produced highly defined nanostructures down to 4.5 nm half pitch, without the need for expensive equipment upgrades.
"In addition to making the bits, we demonstrated that they can be used to store data," said Dr Yang.
This "salty developer solution" method, which was invented by Dr Yang when he was a graduate student at the MIT, means a HDD that currently holds 1 TB of data could, in the future, hold 6 TB of data in the same size unit.