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Tai Min,
Qiang Chen,
R. Beach,
G. Jan,
Cheng Horng,
W. Kula,
T. Torng, R. Tong,
T. Zhong,
D. Tang,
Pokang Wang,
Mao-min Chen,
J.Z. Sun,
J.K. Debrosse,
D.C. Worledge,
T.M. Maffitt,
W.J. Gallagher
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ABSTRACT: Key design parameters of 64 Mb STT-MRAM at 90-nm technology node are discussed. A design point was developed with adequate TMR for fast read operation, enough energy barrier for data retention and against read disturbs, a write voltage satisfying the long term reliability against dielectric breakdown and a write bit error rate below 10<sup>-9</sup>. A direct experimental method was developed to determine the data retention lifetime that avoids the discrepancy in the energy barrier values obtained with spin current- and field-driven switching measurements. Other parameters detrimental to write margins such as backhopping and the existence of a low breakdown population are discussed. At low bit-error regime, new phenomenon emerges, suggestive of a bifurcation of switching modes. The dependence of the bifurcated switching threshold on write pulse width, operating temperature, junction dimensions and external field were studied. These show bifurcated switching to be strongly influenced by thermal fluctuation related to the spatially inhomogeneous free layer magnetization. An external field along easy axis direction assisting switching was shown to be effective for significantly reducing the percentage of MTJs showing bifurcated switching.
IEEE Transactions on Magnetics 07/2010; · 1.36 Impact Factor
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R. Beach,
T. Min,
C. Horng,
Q. Chen,
P. Sherman,
S. Le,
S. Young,
K. Yang,
H. Yu,
X. Lu, [......],
M. Qazi,
J. DeBrosse,
M. Gaidis,
S. Kanakasabapathy,
Y. Lu,
J. Nowak,
E. O'Sullivan,
T. Maffitt,
J.Z. Sun,
W.J. Gallagher
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ABSTRACT: We have demonstrated a robust magnetic tunnel junction (MTJ) with a resistance-area product RA=8 Omega-mum<sup>2</sup> that simultaneously satisfies the statistical requirements of high tunneling magnetoresistance TMR > 15sigma(R<sub>p</sub>), write threshold spread sigma(Vw)/ <7.1%, breakdown-to-write voltage margin over 0.5 V, read-induced disturbance rate below 10<sup>-9</sup>, and sufficient write endurance, and is free of unwanted write-induced magnetic reversal. The statistics suggest that a 64 Mb chip at the 90-nm node is feasible.
Electron Devices Meeting, 2008. IEDM 2008. IEEE International; 01/2009
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ABSTRACT: We present the GT-IIR language recognition system submitted to the 2005 NIST Language Recognition Evaluation. Different from conventional frame-based feature extraction, our system adopts a collection of broad output scores from different language recognition systems to form utterance-level score distribution feature vectors over all competing languages, and build vector-based spoken language recognizers by fusing two distinct verifiers, one based on a simple linear discriminant function (LDF) and the other on a complex artificial neural network (ANN), to make final language recognition decisions. The diverse error patterns exhibited in individual LDF and ANN systems facilitate smaller overall verification errors in the combined system than those obtained in separate systems
Speaker and Language Recognition Workshop, 2006. IEEE Odyssey 2006: The; 07/2006
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Yimin Guo,
P. Wang,
M.-M. Chen,
C. Horng,
T. Min,
L. Hong,
O. Voegeli, R. Tong,
P. Chen,
S. Le,
J. Chen,
T. Zhong,
L. Yang,
G. Liu,
Y. Chen,
S. Shi,
K. Yang,
D. Tsang
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ABSTRACT: Soft-adjacent magnetic layer (SAL) coupled MRAM arrays have been developed for high density, low current applications. Instead of using shape anisotropies, free layer elements have been used strongly coupled with their adjacent-soft magnetic bit lines, forming coupling anisotropies (perpendicular to bit line directions) on free layer elements to hold stored data. MRAM array test data show that the use of the coupling anisotropies is more stable, less dependent upon free element shape distortions, and give smaller switching variation at very low switching bit line currents. It is revealed that flux closure with SAL prevents free element from middle resistance state caused by vortex.
Journal of Applied Physics 05/2005; 97(10):10P506-10P506-3. · 2.17 Impact Factor
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ABSTRACT: Measured data of a 5-Channel 11GHz Contiguous Band Multiplexer meeting INTELSAT VI requirements is presented. No compensating networks or dummy channels are used in the physical realization of the multiplexer, thus advancing the state-of-the-art.
Microwave Symposium Digest, 1982 IEEE MTT-S International; 07/1982
