updated 08:00 pm EDT, Fri May 4, 2012
Research may lead to faster, longer lived media
A thirty-year-old concept in computer memory may be making a resurgence. Material engineers at Johns Hopkins University have turned to diamonds to change the properties of elements used in phase change memory such as used in CD-RW and DVD-RW discs. This development could lead to higher data density storage systems that both last longer and react quicker than current optical, flash, or magnetic media.
Current phase change memory materials are composed of primarily germanium (Ge), antimony (Sb), and tellurium (Te). This material, known as GST phase change memory, is used in modern CD and DVD-RW media. As currently used, when exposed to heat such as that generated by the material being lased, an area of the alloy can change from an amorphous, or unorganized, state to a crystalline state, where the atoms are lined up in long chains. The difference in refraction between the two states can be read by a laser, which makes the material ideal for optical media.
Using diamonds to apply pressure to the GST during manufacture, the Johns Hopkins researchers discovered that they could change the physical properties of the base media, slowing down the time of the change from an amorphous to a crystalline state. In doing so, the engineers were able to vary static states of the material more than simply amorphous or crystalline, allowing for a higher data density per unit area of media.
Various manufacturers have been developing phase change memory. IBM is predicting five million write cycles on the new memory, where current flash memory systems can tolerate approximately 100,000 write cycles. No estimation has been made in regards to the magnitude of the data density increase.