Buckyballs boost flash memory

Buckyball memory

There’s a problem on the horizon for memory chips called voltage scaling. It comes about because of a fundamental asymmetry in the design of nonvolatile charge-based memory.

These chips need to store data for about 10^12 times longer than it takes to program or erase. That’s why it’s novolatile. This asymmetry is usally achieved by applying an external voltage to program and erase the memory. But as more memory gets packed into the same area, it becomes hard to supply the right amount of voltage. What’s needed is a material that has a similar or better retention to program/erase time ratio but can be accessed with a lower voltage.

The current favourite to improve the next gen of memory chips is a technology called metal nanocrystal memory in which data is stored in tiny crystals of metal. But it looks as if this technology can easily be made even better than anyone was expecting.

Enter C60 buckyballs, the famous carbon footballs named after the architect Buckminster Fuller who popularised the geodesic dome. Tuo-Hung Hou and a few buddies at Cornell University in New York state has built and tested a new type of nonvolatile memory in which the data is stored in single molecules of C60. The molecules are relatively easy to embed in silicon because they do not clump together. They also have well defined and easily accessible energy levels that have to be overcome by tunnelling to store and erase data.

The team say that buckyballs offer a huge improvement in the data retention time compared to the program/erase time compared with today’s technology. But perhaps more importantly, buckyballs also improve the retention to program/erase time ration of metal nanocrystal memory by a whole order of magnitude. That means they could be added to the next gen of memory relatively easily.

Does that mean buckyballs will sit at the heart of future iPods? Could be.

Ref: arxiv.org/abs/0803.4038: Nonvolatile Memory with Molecule-Engineered Tunneling Barriers

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