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M -RAM (Magnetoresistive – Random Access Memory) Kraków, 7 XII 2004r
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M-RAM M. Bernacki, S. Wąsek Information flux. Information Outside word Input Output Information transmission Information Processing Information storage DRAM, MRAM Magnetic (HDD) Optical (CD, DVD)
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M-RAM M. Bernacki, S. Wąsek Memory categories. WHY DO WEE NEED M-RAMMEMORY ????
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M-RAM M. Bernacki, S. Wąsek Basic attractions of M-RAM. Nonvolatility; Speed; Low-power consumption; Scalability.
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M-RAM M. Bernacki, S. Wąsek Basic attractions of M-RAM. Transfer data to microprocessor without creating a bottleneck!
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M-RAM M. Bernacki, S. Wąsek History and development... M-RAM – quick view. Magnetoresistivity. AMR effect - 80-th. GMR effect - 80-th. TMR effect – 1995 year. M-RAM based on:
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M-RAM M. Bernacki, S. Wąsek Storage and states of a bit. Storage state: DRAM: charge of capacitor. Flash, EEPROM: charge on floating gate. FeRAM: charge of a ferroelectric capacitor. TMR [%] Field [Oe] MRAM: charge and spin. „1” „0” Soft ferromagnet Insulator Hard ferromagnet
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M-RAM M. Bernacki, S. Wąsek Implementation of 1-MTJ / 1-transistor cell. Word line NiFe (free layer) CoFe (fixed layer) Ru CoFe (pinned layer) Al 2 O 3 (tunneling barrier) SAF
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M-RAM M. Bernacki, S. Wąsek Write. Word line With digit line current Without digit line current
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M-RAM M. Bernacki, S. Wąsek Write. Word line RA [kOhm-um 2 ] Easy axis field [Oe]
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M-RAM M. Bernacki, S. Wąsek Read. Word line
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M-RAM M. Bernacki, S. Wąsek Sizes of MTJ. Ferromagnet I Tunnel barrier Ferromagnet II NiFe (free layer) CoFe (fixed layer) Ru CoFe (pinned layer) Al 2 O 3 (tunneling barrier) 4nm 1..2nm 3nm
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M-RAM M. Bernacki, S. Wąsek Other MRAM cell architectures. Twin cell arrays: Circuit is faster than the 1T1TMR implementation. Less atractive on a cell density and cost basis. Diode cell: SOI diodes allow the integration of a memory with most circuits without sacrificing silicon wafer surface area. SOI diodes suitable for this aplication haven’t been developed yet. Transistorless array: Large reduce in cell area. Complex circuity required to read bit state, slow read.
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M-RAM M. Bernacki, S. Wąsek MRAM 32Kb memory segment. Bit line 31 Digit line Word line Bit line 0 Word line
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M-RAM M. Bernacki, S. Wąsek Reference generator. R MAX R MIN Bit line Digit line Word line R REF = 1/2(R MAX + R MIN )
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M-RAM M. Bernacki, S. Wąsek 1Mb MRAM architecture. Available modes: Active mode Sleep mode Standby mode
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M-RAM M. Bernacki, S. Wąsek Examples and performance of M-RAM technology. Freescale semiconductors –2003/2004. Technology: 0.18mikrons, 5-level metal CMOS, copper interconnects; Capacity: 4MB; Access time: 15-20ns Technology: 0.6um, 5-level metal CMOS, copper interconnects; Capacity: 1MB Access time: 35ns Motorola semiconductors –2002.
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M-RAM M. Bernacki, S. Wąsek Roadmap to future storage technologies. RRAM with CMR
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M-RAM M. Bernacki, S. Wąsek Bio – MRAM, vision for tomorrow? MRAM array Biomolecule labeled by magnetic markers
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M-RAM M. Bernacki, S. Wąsek References. Wykład z przedmiotu „Magnetyczne nośniki pamięci”, AGH; Materiały z Uniwersytetu Bielefeld: wykład „Thin films and nanostructures”; Materiały seminaryjne z „Motorola Labs”; Materiały z sympozjum „VLSI symposium 2002”; www.freescale.com www.freescale.com www.motorola.com www.motorola.com
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M-RAM M. Bernacki, S. Wąsek Dziękujemy za uwagę
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