A novel form of computer memory that is faster and more efficient than existing components has been revealed by US scientists.
The 鈥減hase-change鈥� memory stores binary information by switching sections of a semiconducting alloy between an ordered, crystalline phase and a disordered, amorphous phase. It has the potential to be far more efficient than existing forms of memory but has proven difficult to get working perfectly.
The new memory is made from doped germanium-antimony alloy. The researchers succeeded in making components at just 20 nanometres in diameter, which are used to store a binary bit of information. This is substantially smaller than the smallest writable section of flash memory. In addition, it was found to be between 500 and 1000 times faster than flash, while requiring about half as much power.
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鈥淵ou can do a lot of things with this phase-change memory that you can鈥檛 do with flash,鈥� says Spike Narayan, senior manager of nanoscale science at IBM, who led the work.
Continuous power
The phase change memory is also non-volatile. The fastest and most forms of computer memory 鈥� SRAM and DRAM 鈥� must be powered continuously and repeatedly refreshed. These 鈥渧olatile鈥� forms of memory lose their stored information whenever the power supply is cut off.
鈥淵ou can replace discs, do instant-on computers, or carry your own fancy computer application in your hand,鈥� Narayan adds. 鈥淚t would complement smaller technology if manufacturers wanted to conjure things up.鈥�
The research was carried out by researchers at IBM鈥檚 Almaden Research Lab in New York, US, Japanese company Macronix and German firm Qimonda. Technical details of the research will be presented at the 2006 International Electronic Devices Meeting in San Francisco, US, in February 2007.
Ones and zeros
Most computer memory uses the presence or absence of electrical charge contained in a tiny region of material to represent individual ones and zeros of binary information.
The improved efficiency could help boost phase-change memory鈥檚 chances of replacing flash as the electronics industry continues to make devices smaller and more powerful, its makers say.
鈥淭his is a much more robust memory technology,鈥� Narayan says. 鈥淚t will be used more and more as flash gets into more and more trouble at small dimensions.鈥�
