Scientists at Philips Research have developed a phase-change memory promising to match the speed, density, low-voltage and low-power consumption requirements of future deep sub-micron silicon chips.
Unlike existing non-volatile memory technologies, such as Flash memory, the performance of this new memory improves in virtually every respect the smaller it is made, Philips purported.
Phase-change materials change their physical properties depending on whether they are in an amorphous or crystalline phase and are widely used in optical storage media such as DVD recordable and rewritable discs.
In these discs, the reflectivity of the material changes, with a laser used to both heat the material to the required temperature in order to switch it between its amorphous and crystalline phases, as well as to detect the change in its reflectivity.
Philips’ new solid-state memory cell employs similar phase-change materials deposited as an ultra-thin film on the surface of a silicon chip. The technique uses an electric current to switch it between phases and to detect the resultant change in its electrical resistance, the company explained. Although similar memory devices have been investigated before, Philips believes this “line-cell” phase-change memory has the potential to meet both the performance and scaling requirements of future chips.
The company said the key to its memory cell lies in the structure and materials used. Previously, memory cells based on phase-change materials have suffered from the need for relatively high voltages that must be