Hitachi plans SPRAM R&D spin-off

SAN JOSE: Japan's Hitachi is planning to spin off its SPRAM R&D efforts into a new company, but yet no decision has been made. More details about its spin-transfer torque RAM (SPRAM) technology are expected to be revealed at the Symposium on VLSI Technology to be held in Honolulu, Hawaii, from June 15-17.

SPRAM, the next-generation MRAM or memory that uses the magnetism of electron spin to provide non-volatility, is said to have unlimited fortitude but difficult to manufacture in mass amount. Spin-transfer torque random access memory (STT-RAM) technology is a second-generation magnetic-RAM technology .It can solve some of the problems posed by conventional MRAM structures. STT-RAM technology can eventually replace DRAM, NAND and MRAM, said Grandis Inc, a developer of STT-RAM technology.

Also, Everspin is aiming its 16-Mbit MRAM for the SRAM replacement, data retention and related markets. According to Hitachi, 'Multi-level-cell spin-transfer torque memory is formed with series-connected magneto tunnel junctions (MTJ) and the series MTJs (with differently sized areas) have shown multi-level resistance due to the combination of their magnetization directions. In the mean time, Hitachi and its partner, Tohoku University, refer to their STT-RAM technology as SPRAM, which has been into R&D since 2002.

They presented a paper on a 2-Mbit chip in 2007, followed by a 32-Mbit device last year and erstwhile, reported SPRAM for 6F2 and 4F2 cell sizes.

A recent paper cited that using this scheme, the SPRAM can afford to accept the DDRx-SDRAM compatible interface, because the proposed scheme is a similar sequence to the DRAM operation.

According to Hitachi, SPRAM will truly cover the area of the NAND flash memory, file memory region with infinite number of writing cycles. At VLSI, Hitachi intends to take the next step, which is possibly a NAND replacement and it also plans to devise a 16- and 64-Mbit device in 2012, and a 256-Mbit and 1-Gbit chips by 2015.

It is also being said that Hitachi wouldn’t sell the devices under its own name. This would mean that it would be spinning off its SPRAM technology into a new company and the formulation of our production is being discussed, said the company.