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Researchers at Numonyx, a Californian flash memory chip maker, have discovered that the GST material used to store data on optical discs could also be used in flash memory.

Current flash memory stores data in the form of an electronic charge held in a transistor. That works well when transistors are 65nm wide and in the 45nm transistors due to come into use.

But according to the Numonyx researchers, once you try to shrink them to 20nm, the transistor quickly degrades. Flash eventually loses the ability to retain data, as it retains a tiny amount

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of charge each time they are written and erased. Currently that amounts to around 10,000 cycles, probably enough to ensure the lifetime of the memory is longer than the device in which it is used. But at 20nm, charge retention builds up too quickly.

Numonyx's solution is to apply some GST to each transistor. As a charge is applied to the transistor it heats the GST and changes its properties, in the same way that a laser in an optical drive does to the GST layer on a CD or DVD.

The researchers are confident that they can shrink the GST cell sizes in what they are calling phase change memory (PCM) down to 5nm, while building chips than have at least one million write-erase cycles. And as an added advantage, since the quantity of GST decreases as the cell gets smaller, the amount of power required to change its state decreases.

Numonyx is currently showing PCM to device makers, but admits that it has its work cut out given that the current technology has at least 10 years to run.