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Posted: Mar 24, 2011
Different approaches to increase the storage capacity of flash memories
(Nanowerk News) There is a big demand for flash memories that can store even more data. However, it is now necessary to use new materials and technologies to improve flash memories and researchers worldwide are trying different approaches to achieve this aim. The project REALISE has developed a material and a processing technique now ready for industrial application.
Researchers are investigating different ways to increase the storage capacity of the computer storage chips called flash memories. Within the EU-funded project REALISE (Rare earth oxide atomic layer deposition for innovations in electronics), coordinated by Tyndall National Institute in Ireland, scientists are developing flash memories with improved storage capacity. To achieve this improvement new materials have to be introduced.
In REALISE low-cost rare earth oxides form very good electronic insulators, which are reducing the interference between adjacent memory cells. The scientists have made an insulator, containing zirconium oxide and a smaller amount of lanthanum oxide, named LZO. This structure will respond heavily to electric fields. Through electrical tests the scientists found that nanometer-thin films of LZO with a designed structure showed a three-fold improvement, in insulating properties of importance, compared to alumina. Alumina was earlier the best material in this regard. This result means that it is possible to manufacture electronic devices three times smaller than before and the working lifetime is doubled. The researchers use a process called ALD, atomic layer deposition, to put the rare earth oxides atom by atom onto the flash memories and integrate them properly.
Another way towards better memory chips having longer lifetimes and faster write speed than today's flash memories is investigated by scientists from University of Wisconsin-Madison, Nanjing University, University of Michigan, Penn State University and Cornell University. They are improving ferroelectric materials' performance through a system that, in a spontaneous manner, forms nanosized spirals of the electric polarization at controllable intervals, which could give the polarization switching natural budding sites. This would decrease the power necessary to flip each bit. Researchers at the Chung Hua University, the Industrial Technology Research Institute and the National Chiao Tung University in Taiwan have instead worked on highly thermal stable iridium nanocrystals embedded in SiO2 matrix, which they suggest could improve the performance of flash memories.
We will soon be able to store much more on our flash memories if everything goes according to plans. The REALISE project's researchers anticipate that if a large flash memory producer uses LZO for making flash memories better, these devices may be on the market within a few years.