Novel memory hierarchy with e-STT-MRAM for near-future applications

Among various kinds of nonvolatile memory developed, spin torque transfer (STT)-MRAM has the highest write access speed and highest endurance (close to practically unlimited endurance). Hence, embedded (e-) STT-MRAM can cover various kinds of working memory applications that conventionally uses SRAM and e-DRAM. In advanced processors or SoCs, static power of SRAM and e-DRAM has been increased with CMOS scaling and becomes a major part of power consumed in those semiconductor chips. Although “Power gating (PG)” technique enables reduction in the leakage power of SRAM or eDRAM effectively, it can be used only when the memory data can be lost while application is not running (long standby state; >1us).