MRAM: Pole Position In The Race For Succession

No other memory technology even comes close to being as advanced in its development as MRAM (magneto-resistive random access memory), which was presented by Infineon in June 2004 in what is currently the largest capacity, 16 MB. The supporters of MRAM, most notably Infineon and Freescale, assume that MRAM has the potential to make life hard not only for Flash but for DRAM and SRAM as well. The principle of MRAM is based on the storage of data with magnetic storage elements that are positioned on a silicon substrate.

MRAM (Magneto-resistive Random Access Memory)

The strengths of MRAM lie in the unlimited number of write cycles (Flash: typically 100,000 to a million cycles) and write and access speeds that have been increased to an enormous degree. "The time it takes to write the first information bit to the MRAM chip is about a million times shorter than the time it takes to write to a Flash memory. The time needed to read the first bit from the MRAM is shorter than with a NOR Flash chip by a factor of about three and about 1000 times shorter than with a NAND Flash chip", states Dr. Gerhard Müller, senior director of technology development in the Memory Products Business Group at Infineon Technologies.

Freescale is already manufacturing MRAM chips as samples and plans to offer the memory commercially in the form of a 4 Mbit chip in the coming year. The company did not give any details about areas of application.

Critics of the technology wonder whether MRAM can ever attain the cell sizes of Flash. According to Infineon, the cell sizes of Flash are currently at 0.1 µm², while a 16 Mbit MRAM chip has only reached 1.42 µm². Moreover, it is not clear whether the production costs of MRAM can be pushed to the level of Flash.

At Freescale, however, the opinion is that the development of MRAM has a much steeper learning curve than there was with Flash. "We have no reason to believe that MRAM will be more expensive to produce in a few years than Flash is," Weisman says. "We are still a good six to seven years off from the point at which MRAM can rival Flash memory in terms of bit density and price." However, he could not say precisely when they will have caught up with Flash: "that also depends on the development of Flash memory. The problem is that we are dealing with a moving target." Both Freescale and Infineon believe that MRAM has what it takes to replace Flash, and even DRAM/SRAM in the future. It thus may come as close as possible to a "universally usable memory".