DocumentCode :
1052419
Title :
MgO-Based Tunnel Junction Material for High-Speed Toggle Magnetic Random Access Memory
Author :
Dave, R.W. ; Steiner, Gerald ; Slaughter, J.M. ; Sun, J.J. ; Craigo, B. ; Pietambaram, S. ; Smith, K. ; Grynkewich, G. ; DeHerrera, M. ; Akerman, J. ; Tehrani, S.
Volume :
42
Issue :
8
fYear :
2006
Firstpage :
1935
Lastpage :
1939
Abstract :
We report the first demonstration of a magnetoresistive random access memory (MRAM) circuit incorporating MgO-based magnetic tunnel junction (MTJ) material for higher performance. We compare our results to those of AlOx-based devices, and we discuss the MTJ process optimization and material changes that made the demonstration possible. We present data on key MTJ material attributes for different oxidation processes and free-layer alloys, including resistance distributions, bias dependence, free-layer magnetic properties, interlayer coupling, breakdown voltage, and thermal endurance. A tunneling magnetoresistance (TMR) greater than 230% was achieved with CoFeB free layers and greater than 85% with NiFe free layers. Although the TMR with NiFe is at the low end of our MgO comparison, even this MTJ material enables faster access times, since its TMR is almost double that of a similar structure with an AlO _ x barrier. Bit-to-bit resistance distributions are somewhat wider for MgO barriers, with sigma about 1.5% compared to about 0.9% for AlO _ x . The read access time of our 4 Mb toggle MRAM circuit was reduced from 21 ns with AlO _ x to a circuit-limited 17 ns with MgO.
Keywords :
MgO; magnetic random access memory (MRAM); magnetic tunnel junction (MTJ); toggle switching; tunneling magnetoresistance (TMR); Annealing; Circuits; Magnetic materials; Magnetic properties; Magnetic semiconductors; Magnetic switching; Magnetic tunneling; Random access memory; Semiconductor materials; Tunneling magnetoresistance; MgO; magnetic random access memory (MRAM); magnetic tunnel junction (MTJ); toggle switching; tunneling magnetoresistance (TMR);
fLanguage :
English
Journal_Title :
Magnetics, IEEE Transactions on
Publisher :
ieee
ISSN :
0018-9464
Type :
jour
DOI :
10.1109/TMAG.2006.877743
Filename :
1661934
Link To Document :
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