Fujitsu Laboratories, Inc. has been working on ways to improve hard drive technology with the end result of increased and stabilized platter densities. One of Fujitsu Lab’s works in progress is to increase the thickness of the lubricant layer on hard disk media (PDF, March 2005). Fujitsu claims this is just one more step on the way to creating one terabit per square inch densities by 2010.

Fujitsu Laboratories, Inc. has been working on ways to improve hard drive technology with the end result of increased and stabilized platter densities. One of Fujitsu Lab’s works in progress is to increase the thickness of the lubricant layer on hard disk media. Fujitsu claims this is just one more step on the way to creating one terabit per square inch densities by 2010.

Why? Hard disk drive media is comprised of four layers: a substrate layer, a magnetic layer where data is recorded, a protective layer to keep the magnetic layer from corroding, and a thin layer of lubricant to reduce friction between the read/write heads and the protective layer, even though the heads never actually touch either layer. To increase media densities the protective layer must be made thinner, and the drive head lowered to even closer to the platter. Unfortunately, with a thinner protective layer, the lubrication layer is even more important — without the lubrication layer the protective layer will heat up and the magnetic surface will corrode.

Current lubrication layer technology is about 2nm high. The read head is placed approximately 10nm above a 5nm protective layer during a write operation. Unfortunately, the head cannot be placed any closer because the lubrication layer needs some empty space to work effectively (at least, for any long periods of time). By reducing the lubrication height and bonding it to the protective layer, Fujitsu claims the four basic layers are reduced to three, and the lubrication height is reduced dramatically. With the lubricant bound to the surface of the protective layer, the drive head can be lowered dramatically as well. The end result means tinier bits since the drive head can get even closer to the media.

Fujitsu has successfully increased the effectiveness of the lubricant layer 150% by bonding the thicker layer to the protective layer using ultraviolet radiation. The company claims: