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Elpida Touts ReRAM As Possible DRAM Replacement

Tom Jowitt is a leading British tech freelance and long standing contributor to TechWeek Europe

ReRAM, a new memory chip prototype, has been developed to be fast as DRAM but able to retain data when power is cut

Japanese memory maker Elpida Memory has produced a ReRAM memory prototype which has speeds comparable to DRAM, but with no loss of data when the power is switched off.

As the moment dynamic random access memory (DRAM) dominates the computing sector, and is commonly used in almost all desktops and laptops. However, there is a downside to DRAM, it needs power in order to constantly “refresh” the memory to stop data being lost.

An alternative would be NAND Flash memory, usually found in memory cards, USB sticks and solid state drives, but the issue with Flash memory is that it is slow when compared to RAM, especially when writing large amounts of data.

ReRAM Prototype

This is where ReRAM, resistive memory, comes in. It has a write speed of 10ns, about the same as DRAM, and write endurance of more than a million times and a write speed of 10 nanoseconds (ns) – 10 times greater than NAND flash.

Elpida recently revealed the development of its first-ever, high-speed, non-volatile resistance memory (ReRAM) prototype, with a capacity of 64MB in 50nm process technology. The company plans to commercialise a 30nm version together with Sharp in 2013.

This next generation RAM memory is classed as non-volatile memory, meaning that it retains data without power.

“ReRAM (Resistance Random Access Memory) is next-generation semiconductor memory technology that uses material which changes resistance in response to changes in the electric voltage,” said Elpida.

“This new type of non-volatile memory can store data even when the power supply is turned off. Its most attractive feature is that it can read/write data at high speeds using little voltage,” the company said.

Elpida said it plans to continue development toward a 2013 goal of volume production of ReRAM in the gigabit capacity class using the 30nm process technology. Providing it can be delivered at a low cost, its reduced memory power consumption would make it ideal for smartphones, tablets, and ultra thin laptops.

DRAM Limitations

Referring to the problems with DRAM, Dr Richard Boardman, from the University of Southampton’s School of Engineering Sciences, told the BBC, “When the power disappears, the content of the memory is forgotten.

“This process does not take long – within a few seconds it is practically unreadable, even with sophisticated tools. Secondly, because the DRAM must always remain powered, this increases standby consumption for devices, along with the risk that the content will vanish if the power does,” he added.

“Flash can only write data tens or hundreds of thousands of times to the same spot before the risk of device failure becomes high,” Boardman said. “This might sound like a lot, but without technologies in place to spread the data writes around, this limit can be reached very quickly.”

Memory Developments

It is worth noting that Elpida is not the only company developing new memory technology such as ReRAM.

Earlier this month, the American company Venray Technology touted its ability to combine CPU cores with DRAM memory on the same piece of silicon. And companies such as HP continue to develop their own memristors in a race to be the first to market in 2013.

Last July, IBM claimed  to have made a “significant advancement” in the field of computer memory, with a promising new technology called phase-change memory (PCM). IBM said that PCM can potentially offer non-volatile and high-density data storage that is 100 times faster and far more durable than Flash, the most commonly used non-volatile memory technology today.

Merger Denial

Despite its promising technology, Elpida has been forced to deny market rumours that it is merging with Micron Technology or Taiwanese chipmaker Nanya, both rival DRAM makers.

“Recently Japanese and overseas media have issued reports concerning Elpida Memory that were based on speculation,” said the company. “We wish to emphasise that these reports are not based on information Elpida itself has released.

“Furthermore, they have no factual basis,” it added. “Lastly, Elpida declines to comment on reports that are based on rumour or speculation.”