Read/Write Robustness Estimation Metrics for Spin Transfer Torque (STT) MRAM Cell
Elena I. Vatajelu1, Rosa Rodriguez-Montañés2, Marco Indaco1, Michel Renovell3, Paolo Prinetto1 and Joan Figueras2
1Politecnico di Torino, Dip. di Automatica e Informatica, Turin, Italy
2Universitat Politécnica de Catalunya (UPC) Dept. of Electronic Engineering Barcelona, Spain
3LIRMM, Montpellier, France
The rapid development of low power, high density, high performance SoCs has pushed the embedded memories to their limits and opened the field to the development of emerging memory technologies. The Spin- Transfer-Torque Magnetic Random Access Memory (STTMRAM) has emerged as a promising choice for embedded memories due to its reduced read/write latency and high CMOS integration capability. Under today aggressive technology scaling requirements, the STT-MRAM is affected by process variability making robustness evaluation an important concern. In this paper, we provide new metrics for robustness prediction of an STT-MRAM memory cell. Independent Robustness Margin metrics are defined for Read Operation and Write Operation based on the electrical characteristics of the memory cell and the fabrication induced variability. These metrics are used to estimate the extreme parameter variation causing the cell failure, Current Noise Margins and the Failure Probability of the STT-MRAM cell.
Keywords: STT-MRAM, Robustness, Process variability, Robustness margin metrics.
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