STT-MRAM: A Robust Embedded Non-Volatile Memory with Superior Reliability and Immunity to External Magnetic Field and RF Sources

We report STT-MRAM’s robustness, superior reliability and immunity performance to external magnetic field and RF sources for next-generation embedded-MRAM (eMRAM) technology based on 22FDX
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+RF+MRAM. Using 40Mb eMRAM integrated in 22FDX
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, we demonstrate Write/Read repeatability performance with BER variation of <0.2 PPM with ECC-OFF and zero failure with ECC-ON at -40~125°C. We show angle dependence of standby magnetic immunity and ways to improve it with optimized shielding designs. Using a specially designed RF-MRAM EMI chip, we demonstrate no impact of RF interference on MRAM and vice versa. Furthermore, using optimized MTJ process, design and testing schemes, we show <2 PPM post 5x solder reflow performance and zero mean endurance failure after 100K cycles at -40°C.