Influence of the Reference Layer Composition on the Back-End-of-Line Compatibility of Co/Ni-Based Perpendicular Magnetic Tunnel Junction Stacks
| Autor: | Sofie Mertens, T. Lin, Geoffrey Pourtois, Laurent Souriau, Yoann Tomczak, Johan Swerts, Kiroubanand Sankaran, Arnaud Furnemont, Sven Van Elshocht, Woojin Kim, Sebastien Couet, Diana Tsvetanova, Enlong Liu, Gouri Sankar Kar |
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| Rok vydání: | 2016 |
| Předmět: |
010302 applied physics
Dynamic random-access memory Materials science Annealing (metallurgy) 02 engineering and technology Polarizer 021001 nanoscience & nanotechnology 01 natural sciences Electronic Optical and Magnetic Materials law.invention Tunnel magnetoresistance Back end of line Nuclear magnetic resonance CMOS Stack (abstract data type) law 0103 physical sciences Perpendicular Electrical and Electronic Engineering Composite material 0210 nano-technology |
| Zdroj: | IEEE Transactions on Magnetics. 52:1-4 |
| ISSN: | 1941-0069 0018-9464 |
| DOI: | 10.1109/tmag.2016.2515109 |
| Popis: | Spin-transfer torque magnetic random access memory (STT-MRAM) is currently explored to challenge the dynamic random access memory and embedded memory applications. Perpendicular magnetic tunnel junction (p-MTJ) stacks used in the STT-MRAM must be compatible with CMOS back-end-of-line processing, such as high perpendicular magnetic anisotropy, high tunnel magnetoresistance (TMR), and intact resistance area (RA) product at temperatures, as high as 400 °C. In this paper, we deposited a bottom-pinned Co/Ni-based p-MTJ stack with a trilayered Co/spacer/CoFeB as a reference layer and a CoFeB film as the storage layer. By replacing the standard Ta spacer material with CoFeBTa, the thickness of the spacer layer can be increased from 4 to 8 A without TMR and RA penalty, which is beneficial to process controllability. Moreover, the TMR increases for an 8 A CoFeB polarizer from 125% to 145% for a similar RA product after a 300 °C 30 min anneal. In addition, the thermal budget of the p-MTJ stack containing a CoFeBTa spacer was improved. The p-MTJ stack with a 12 A CoFeBTa reference layer spacer can even withstand annealing at 400 °C for 90 min and can retain a TMR value of 100% at RA 10 $\Omega \cdot \mu \text{m}^{2}$ , while TMR dropped below 40% for the p-MTJ stack containing a pure Ta spacer layer. |
| Databáze: | OpenAIRE |
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