STT-MRAM technology is a promising high-density alternative to existing memory technologies, like SRAM and DRAM. Together, imec and the program members aim to explore the potential of STT-MRAM, including performance below 1nanosecond (ns) and scalability beyond 10 nanometers (nm) for embedded and standalone applications.
MRAM technology is a non-volatile memory that has not inherited the disadvantages NAND flash-based storage - it does not wear out and it is also not constrained in terms of density.
MRAM stores information as a magnetic orientation rather than as an electrical charge. This provides a much higher read and write performance that is much closer to DRAM speeds than flash because bits are read by testing with voltage, not current, and written with a small current boost, not a huge charge. Current DRAM latency is less than 10 nanoseconds ; MRAM is currently around 50nsec, and flash is much slower at 20 microseconds to 200 microseconds depending on read or write.) Since there's no charge pump, MRAM doesn't wear out like flash does.
STT-MRAM is based on the principle of spin-torque transfer, which flips a magnetic bit by passing a write current through a permanent magnet layer first to give all the electrons an aligned spin. As those polarized electrons run into and pass through the magnetic bit layer, they torque its magnetic field to effectively flip it. The lack of any external magnetic field could allow allow STT-MRAM circuitry ot be shrunk to DRAM-like densities.
Everspin Technologies recently announced a 64 Mb DDR3 form factor ST-MRAM chip; Crocus Technology is developing a thermal-assisted technology applied with spin-torque; Spin Technologies has an orthogonal MRAM approach promising high densities; and Micron Technology, Qualcomm and Toshiba have all invested in MRAM.
"MRAM has the potential to come to market in the next couple of years in a density, cost and form factor that could obsolete flash solutions overnight," said Mike Matchett, senior analyst and consultant at Taneja Group.
"When nvRAM becomes as fast as DRAM, and in the case of MRAM can also be built into the same silicon as compute, whole new ways of architecting both servers and storage will emerge," Matchett said. "Imagine persistent storage that is potentially as fast as active compute memory. Ultimately, a few years out, we can foresee a total chip-level convergence of storage and compute. If data persistence can be built directly into compute nodes, we'll see some terrific gains in green computing and an explosion in more fabric-like distributed computing," he added.