By now, we are all so used to the ongoing progress in the reduced size and cost of electronic components, as predicted by Moore’s Law, that we have come to regard it as the natural order of things. However, there are physical limits on how densely circuit components can be packed, at least with current silicon-based fabrication.
So it is of some interest that, as reported in an article at Technology Review, Hewlett-Packard has entered into an agreement with the Korean electronics manufacturer Hynix Electronics, to produce memory chips based on memristor technology, for sale beginning in 2013. Memristors are a variety of resistor having two valuable properties:
- The amount of resistance can be varied by the current and voltage applied to the device
- The device “remembers” its set resistance even without power
The devices are made by laying down a series of parallel nano-scale wires on a substrate, coating them with titanium dioxide, and then laying down another layer of wires perpendicular to the first layer. A memristor device is thereby formed at each point where the wires cross. (This is somewhat reminiscent, although on a very much smaller scale, of the magnetic core memories used in early computers, in which tiny magnetic “doughnuts” were strung on a grid of fine wires.) Because the memristor devices can remember their state, they can be used to implement memory, just as transistors in silicon are used in flash memory. However, the memristors can be made much smaller: about 3 nanometers across, compared to about 20 nanometers for the smallest experimental transistors. On their introduction, the new memory devices are expected to deliver a storage density of about 20 GB per square centimeter, roughly double the density of flash memory. Memristors also have a longer expected lifetime, of about 1 million read-write cycles, compared to 100,000 for flash memory, and are expected to consume significantly less power.
Whether or not HP and Hynix make their timetable of having a product by 2013 probably depends on some factors, like unexpected production glitches, that no one can predict right now. Still, it seems that a generalized form of Moore’s Law has a fair amount of life left.