Experimental computer memory could supersede flash

The technology, dubbed FeTRAM (ferroelectric transistor random access memory), is said to combine silicon nanowires with a so-called ferroelectric polymer, a material that switches polarity when electric fields are applied, making possible a new type of ferroelectric transistor.

‘It’s in a very nascent stage,’ said doctoral student Saptarshi Das, who is working with Joerg Appenzeller, a professor of electrical and computer engineering and scientific director of nanoelectronics at Purdue University’s Birck Nanotechnology Center. ‘We’ve developed the theory and done the experiment and also showed how it works in a circuit.’

The FeTRAM technology has non-volatile storage plus the potential to use 99 per cent less energy than flash memory, a non-volatile computer storage chip and the predominant form of memory in the commercial market.

‘However, our present device consumes more power because it is still not properly scaled,’ Das said. ‘For future generations of FeTRAM technologies one of the main objectives will be to reduce the power dissipation. They might also be much faster than another form of computer memory called SRAM.’

The FeTRAM technology reportedly fulfils the three basic functions of computer memory: to write information, read the information and hold it for a long period of time.

‘You want to hold memory as long as possible, 10 to 20 years, and you should be able to read and write as many times as possible,’ Das said. ‘It should also be low power to keep your laptop from getting too hot. And it needs to scale, meaning you can pack many devices into a very small area. The use of silicon nanowires along with this ferroelectric polymer has been motivated by these requirements.’

The new technology also is compatible with industry manufacturing processes for complementary metal oxide semiconductors used to produce computer chips.

The FeTRAMs are similar to ferroelectric random access memories, FeRAMs, which are in commercial use but represent a relatively small part of the overall semiconductor market.

Both use ferroelectric material to store information in a non-volatile fashion but, unlike FeRAMS, the new technology allows for non-destructive readout, meaning information can be read without losing it.

This non-destructive readout is possible by storing information using a ferroelectric transistor instead of a capacitor, which is used in conventional FeRAMs.

Findings are detailed in a research paper that appeared this month in Nano Letters, published by the American Chemical Society. A patent application has been filed for the concept.