June 2005

MRAM has been considered as a potential next-gen memory technology for quite some time, and it was in the spotlight at the VLSI 2005 symposium. NEC and Toshiba jointly unveiled a new Toggle MRAM cell structure in which the magnetic tunnel junction has a multi-layered structured.

Fujitsu Laboratories presented a new approach to MRAM circuity. The company is developing embedded MRAM and they have now proposed a one-transistor/two-magnetic tunnel junction (1T/2MTJ) structure MRAM cell with a direct voltage-sensing scheme, which it said has the advantages of DRAMs. In the proposed 1T/2MTJ cell, two MTJs were connected in series. Fujitsu fabricated the test device with each MTJ measuring 0.2 x 0.4 micron and confirmed the cell operation.

Interesting article from Engineer Live, about MRAM, OUM and FRAM -
MRAM is the highest profile at the moment, with a 4Mbit prototype shown in December (2003) based around a magnetic tunnel junction (MTJ) where magnetic material stores the data bit.
"We are very excited about this," said Saied Tehrani, director of MPEM technology at Motorola Semiconductor division. "It really brings two parts of the industry together - semiconductor and magnetics. We have taken the thin film technology and integrated that with the silicon transistor technology and used the magnetic polarisation to store the data and the silicon transistor for reading and writing the information."
The 4Mbit part is built in 0.18µm technology but for commercial products Motorola is looking at jumping a process generation and going straight to the current leading edge 90nm. This is being developed at a plant in Crolles, France, in a joint development with Franco-Italian chip maker ST Microelectronics and Dutch electronics giant Philips.
This would allow 64Mbits or even 128Mbit stand alone devices to be built, but that is not the aim.
So Motorola is planning to embed MRAM into devices alongside other functions. Tehrani would not comment on what these devices would be, except to say that they would be out on the market in 2005 and Motorola would announce the roadmap later this year. "Microcontrollers are a definite possibility for this technology," he said.

Honeywell International Inc. has posted a data sheet for a 1-Mbit radiation-hard magnetic RAM to its website in the form of a "pdf" file. A source said the Honeywell memory is not a prototype or sample, but a commercial product. However, the specification sheet is labeled "advanced information".

The Honeywell 1-Mbit MRAM, organized as 64K by 16-bits, is fabricated in Honeywell's radiation-hardened 150-nanometer silicon-on-insulator manufacturing process technology, and is designed for use in low-voltage systems operating in radiation environments. The MRAM operates over the full military temperature range and is operated with 3.3-V and 1.8-V power supplies, according to the specification sheet.