Shared-Write-Channel-Based Device for High-Density Spin-Orbit-Torque Magnetic Random-Access Memory

초록

Spin-orbit-torque (SOT) devices are promising candidates for the future magnetic memory landscape, as they promise high endurance, low read disturbance, and low read error, in comparison with spin-transfer torque devices. However, SOT memories are area intensive due to the requirement for two access tran-sistors per bit. Here, we report a multibit SOT cell that has a single write channel shared among multiple bits, which enables an area-efficient memory design by reducing the number of access transistors. All combinations of digital information can be written in the multibit devices with a single current pulse. This functionality is facilitated by the electric field modulation of SOT polarity by tuning the heavy metal-ferromagnet interfacial oxidation state. Centered on the multibit devices, a shared-write-channel (SWC) memory design provides double the device density of current SOT magnetic random-access mem-ory (MRAM). This improvement makes SOT MRAM appealing for its adoption over a wide range of memory hierarchies.