The Magnetoresistive Random Access Memory

MRAM is a type of solid-state memory that can be used to store data even when its power is turned off - a feature known as non-volatility. With read write time comparable to the speed of DRAM, MRAM is a suitable storage medium for cell phone, digital camera, personal digital assistant, and other information appliances. MRAM is physically similar to DRAM in makeup, although often does not require a transistor for the write operation. However, the most basic MRAM cell suffers from the half-select problem, which limits cell sizes to around 180 nm or more.

MRAM is very likely to start to replace NV-SRAM since it must be cheaper to produce a more or less standard die in a standard package than to start adding batteries to the mix. DARPA at least should be happy with its early investments in Motorola and Honeywell research even if this technology doesn’t give us better cell phones or MP3 players. MRAM is a technology that has been around for some time. The challenges are to scale it up to NAND and NOR capacities at the similar or lower costs. MRAM is called “the holy grail” of memory, and has the potential to replace FLASH, DRAM and even hard-discs.

Technology experts believe MRAM will provide the ideal solution for storage needs of today’s electronics. Besides being a faster and more reliable memory solution, it also uses way less power than memory options widely used these days such as DRAM. Magnetic RAM (MRAM) is a new memory technology with access and cost characteristics comparable to those of conventional dynamic RAM (DRAM) and the non-volatility of magnetic media such as disk. Simply replacing DRAM with MRAM will make main memory non-volatile, but it will not improve file system performance.

IBM researchers have demonstrated that MRAM can be six times faster than the industry standard’s dynamic RAM (DRAM), and it is almost as fast as today’s static RAM (SRAM) — a faster, more expensive RAM used in memory caches. MRAM also has the potential to be extremely dense, packing more information into a smaller space. The MRAM have also an important advantage in terms of speed (a gain of 1000 for the write time) over the permanent memories of Flash type that are used today for mobile electronics. At least two commercial efforts- one by Motorola, the other by IBM and Infineon in Munich- plan to begin production of MRAM in 2004.