LONDON – Researchers from the Samsung Advanced Institute of Technology and the department of physics at Sejong University (Seoul, Korea) have reported on a non-volatile resistive RAM with a read-write endurance of more than one trillion cycles.
The passive switching memory is made using asymmetric Ta2O5−x/TaO2−x bilayer structures and has 10-ns switching times, according to the authors of a paper published by Nature Materials.
The devices are of the metal-insulator-metal type with platinum electrodes and experimental results are reported for cell sizes from 50 microns by 50 microns down to 30-nm by 30-nm. The team also prepared samples with double stacked ReRAM cells with linear dimensions of about 90-nm to judge from a scaled scanning electron micrograph and reported on 10 by 10 cell arrays with cell dimensions of 30-nm by 30-nm. The measured activation energy of 1.47-eV provides an estimated retention of greater than 10 years at 85 degrees Celsius.
By combining two devices anti-serially, one above the other, the authors have also circumvented the known problem with cross-bar devices of stray leakage without the need for rectifying diodes or access transistors.
The authors claim to have reduced power consumption compared with other reported ReRAMs and that the high endurance and fast switching make the device suitable for use as working memory as a potential replacement for flash memory.
This read-write endurance would seem to exceed the lifetime memory writing operational requirements for a home computer. Does it make sense to start by deploying this technology to replace flash memory (with limited write cycles) in portions of computers with heavy re-write usage until it is cheap enough for wider deployment?
In mid-May Panasonic reportedly announced it is planning volume production of a 2-Mbit ReRAM in 2012. Nikkei and Reuters are referenced as sources.
Panasonic is known to have researched tantalum oxide ReRAM from presentations at learned conferences such as IEDM 2008.
ReRAM samples should be ready before the end of 2011 and volume production will start at Panasonic's Tonami Plant (Tonami City, Toyama Prefecture) the reports said.
SAIT does not represent what Samsung plans to manufacture, but what could disrupt Samsung any time.
This achievement looks underwhelming because Panasonic did this more than three years ago. But Panasonic will sample it later this year, I hear.
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