报告题目：Spin torque and magnetic memory materials, devices and systems Opportunities and challenges

报 告 人：IBM T. J. Watson Research Center Yorktown Heights, NY 10598, USA

报告时间：2018-10-11 16:00

报告地点：理科楼郑裕彤讲堂

报告摘要：Spin-tranfer-Torque (STT) based devices are being actively pursued by many semiconductor manufacturers today as a memory technology for applications beyond CMOS scaling limit. The chief advantages of the so-called spin-torque magnetic random access memory (STT-MRAM) include simple integration topology, non-volatility in data retention, and potentials for processor-embedded applications. Integration of advanced metal-oxide-metal tunnel junctions into the backend of silicon technologies presents a set of materials and processing challenges that are being aggressively addressed industry-wide. In this talk I review the basic device physics of STT-based nanomagnetic switching, using the characteristics of the two-terminal STT-based tunnel junction as an example. As an example of real-world device and materials complexity, I’ll discuss the dependence of tunnel device STT switching characterstics on junction resistance-area product, and the likely role hot-electron spin-flip scattering plays in these processes. The demand for high area-density circuit for cost-competitiveness, the need for highly reliable switching characteristics for computation, and the nature of finite temperature nanomagnet dynamics combine to generate needs for significantly more spin-current density. For fast, nonvolatile and deterministic manipulation of nanomagnets, and based on present-day device physics understanding, this requires new sources of spin-current to be considered, such as thermal magnonic or spin-orbit-derived spin-currents. I will briefly review recent advances with these new sources of spin currents, and the likely common challenges they will give rise to, in terms of materials and device design and development.