Imec demonstrates record tunneling magnetoresistance for one of the world's smallest perpendicular magnetic tunnel junctions
SAN FRANCISCO - International Electron Devices Meeting 2016 (IEDM) —Dec. 6, 2016— At the 2016 IEEE International Electron Devices Meeting, in a special poster session on MRAM, world-leading research and innovation hub for nano-electronics and digital technology imec presented a 8nm p-MTJ device with 100 percent tunnel magnetoresistance (TMR) and coercive field as high 1500Oe. This world’s smallest device enables the establishment of a manufacturing process for high-density spin-transfer-torque magnetic random access memory (STT-MRAM) arrays that meet the requirements of the 10nm and beyond logic node for embedded non-volatile memory applications. It also paves the way for high density stand-alone applications.
STT-MRAM has the potential to become the first embedded non-volatile memory technology on advanced logic nodes for advanced applications and is also considered an alternative to conventional dynamic random access memory (DRAM). The core element of an STT-MRAM is a magnetic tunnel junction (MTJ) in which a thin dielectric layer is sandwiched between a magnetic reference layer and a magnetic free layer, where writing of the memory cell is performed by switching the magnetization of the free layer. STT-MRAMs exhibit non-volatility, high-speed, low-voltage switching and nearly unlimited read/write endurance. However, significant challenges towards commercialization remain, primarily in scaling the processes for higher densities and in increasing the device switching current.
In addressing these challenges, imec scientists have demonstrated for the first time an electrical functional p-MTJ device as small as 8nm. Despite the small dimensions, the device exhibits a high TMR of 100 percent, a coercivity (Hc) of 1500Oe and a spin torque efficiency -the ratio of the thermal stability and switching current- as high as three. The p-MTJ stack, featuring a free layer and reference layer of CoFeB-based multilayer stacks, was developed on 300mm silicon wafers and the fabrication process is compatible with the thermal budget of standard CMOS back-end-of-line (BEOL) technology.
Moreover, imec integrated arrays of p-MTJ devices into a 1T1MTJ structure to build STT-MRAM Megabit arrays with pitches down to 100nm, proving that the technology meets the dimensional requirements for the 10nm logic node and beyond.
“STT-MRAM is a promising memory concept for future technology nodes, but its scalability towards high densities has always been challenging,” stated Gouri Sankar Kar, distinguished member of technical staff coordinating RRAM, DRAM-MIMCAP, STT-MRAM activities at imec. “Our demonstration of a high-performance p-MTJ device as small as 8nm, combined with a manufacturable solution for a highly scalable STT-MRAM array will open up continued innovations for embedded non-volatile memory applications in the 10nm logic node.”
Imec’s research into advanced memory is performed in cooperation with imec’s key partners in its core CMOS programs including GlobalFoundries, Micron, Qualcomm, Sony and TSMC.
Figure 1 – (a) TMR (tunnel magnetoresistance), (b) Hc (coercivity) and (c) Hoff/Hc (offset field/coercivity, in %) across MTJs of various sizes
Imec is the world-leading research and innovation hub in nano-electronics and digital technologies. The combination of our widely acclaimed leadership in microchip technology and profound software and ICT expertise is what makes us unique. By leveraging our world-class infrastructure and local and global ecosystem of partners across a multitude of industries, we create groundbreaking innovation in application domains such as healthcare, smart cities and mobility, logistics and manufacturing, and energy.
As a trusted partner for companies, start-ups and universities we bring together close to 3,500 brilliant minds from over 70 nationalities. Imec is headquartered in Leuven, Belgium and also has distributed R&D groups at a number of Flemish universities, in the Netherlands, Taiwan, USA, China, and offices in India and Japan. In 2015, imec's revenue (P&L) totaled 415 million euro and of iMinds which is integrated in imec as of September 21, 2016 52 million euro. Further information on imec can be found at www.imec.be.
Imec is a registered trademark for the activities of IMEC International (a legal entity set up under Belgian law as a "stichting van openbaar nut”), imec Belgium (IMEC vzw supported by the Flemish Government), imec the Netherlands (Stichting IMEC Nederland, part of Holst Centre which is supported by the Dutch Government), imec Taiwan (IMEC Taiwan Co.) and imec China (IMEC Microelectronics (Shanghai) Co. Ltd.) and imec India (Imec India Private Limited), imec Florida (IMEC USA nanoelectronics design center).
Hanne Degans, Press Officer, +32 16 28 17 69 // +32 486 06 51 75 // Hanne.Degans@imec.be