Development of scalable High-Speed MRAM technology for system LSI Embedding by NEC
Due to the progress in reducing cell size and the large capacity of system LSI, power consumption has increased. The current demands require reduced power consumption, which is partially accomplished by switching off during stand-by mode, a function that requires easy-use nonvolatile memory. In response to these market demands, NEC developed the world’s fastest SRAM-compatible MRAM with operation speed of 250 MHz in November 2007, and 32 Mbit MRAM for embedding in SoCs in February 2009. To further advance the scaling down of cell size, NEC Corporation (NEC) and NEC Electronics Corporation (NECEL) announced the world’s first development of a magnetic random access memory (MRAM) with current-induced domain wall motion using perpendicular magnetic anisotropy material. Domain wall is an interface separating magnetic domain. The newly developed current-induced domain wall motion writing method, using spin torque and perpendicular magnetization material has a capability of reducing current while writing for a scaled down cell beyond the 55 nanometer process. The newly developed domain wall motion elements are an advanced technology of spintronics which switches magnetization by domain wall motion with spin polarized current. Spintronics, or spin electronics, refers to the study of the role played by electron spin in solid state physics, and possible devices that specifically exploit spin properties instead of or in addition to charged degrees of freedom where as the Spin polarization is the degree to which the electron spin is aligned with a given direction. This successful development shows that high speed MRAM cells can be used to further advance the progress of scaling down size and it has widened the application area of memory changing into MRAM on system LSI.