The emergence of high-density semiconductor-compatible spintronic memory

After many years of research and development, megabit-density spintronic memory, also called magneto-resistive random-access memory (MRAM), may be on the verge of commercial production at several companies, including Honeywell International Inc., Cypress Semiconductor Corp., IBM Corporation, and Motorola Inc. MRAM has been touted as being a universal memory technology, with the high speed of SRAM, the nonvolatility of flash memory (but with much greater erase-write endurance than flash memory), and with storage densities approaching those of DRAM. MRAM is also promoted as being embeddable in conventional CMOS processes with as few as four additional mask steps. Similar advantages are also claimed by proponents of at least two other emerging candidate universal memories: ferroelectric memory and chalcogenide-based phase change memory. This paper focuses on MRAM, and briefly surveys the most promising MRAM technologies, including anisotropic MRAM, spin valve MRAM, pseudo spin valve MRAM, and magnetic tunnel junction MRAM (MTJ-MRAM).