Transcript Presentation - TKS
Magnetic RAM: The Universal Memory
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
Overview
• • • • • • •
Introduction Historical perspective Technical Description Challenges Principals Market impacts Summary
Introduction
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary • • •
Non-volatile
– Information is saved even when there is no power
Immediate boot up
– No need to wait for your computer to boot up
MRAM, SRAM and DRAM
– MRAM is potentially capable of replacing both DRAM, SRAM and many advantages over technology currently used in electronic devices
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary • • •
Introduction
DRAM
– Advantages: cheap – Disadvantages: Comparatively slow and loses data when power is off
SRAM
– Advantages: fast – Disadvantages: cost up to 4 times as much as DRAM loses data when power is off
Flash memory
– Advantages: save data when power is off – Disadvantages: saving data is slow and use lot of power
Historical Overview
Historical Perspective • Why MRAM Became an Important Research Topic Overview Introduction Technical Description – Universal Memory (Computing & Electronics) – “Instant-On” Computing – Read & Write to Memory Faster – Reduced Power Consumption – Save Data in Case of a Power Failure Challenges / Constraints • Modern MRAM Technology Emerged from Several Technologies : – Magnetic Core Memory Principals Market – Magnetoresistive RAM – Giant Magnetoresistance Summary
Magnetic Core Memory
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary • In 1953 a team at MIT called
Whirlwind
introduced the magnetic core memory • Magnetic core memory utilized arrays of thousands of small ring magnets threaded with wires • Data bits were stored and manipulated by sending electric current pulses through the magnets • Magnetic cores were the most reliable and inexpensive memories for almost twenty years Photo Courtesy: Magnetism Group, Trinity College, Dublin
Giant Magnetoresistance Materials
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals • Giant Magnetoresistance Materials (GMR) were discovered in 1989 • By 1991 GMR technology provided a magnetoresistance ratio of 6% (3 times that provided by previous technologies) • Read access time of 50 ns (9 times improvement) • Still not as fast as semiconductor memory • Large size because lines of 1micron were required Market Summary
Technical Overview
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals • 3 MRAM Technologies are Currently Being Developed – Hybrid Ferromagnet Semiconductor Structures – Magnetic Tunnel Junctions – All-Metal Spin Transistors & Spin Valves • Writing Data to a Cell is Similar for all 3 Technologies • Reading a Cell’s Data Reads the Direction of Magnetization of a Ferromagnetic Element, but the Method Varies for Each Technology Market Summary
Basic Principles
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market • The 2 Possible Magnetization States of a Ferromagnetic Element can be Described by a Hysteresis Loop • Magnetization of Film vs. Magnetic Field Diagram Courtesy:
IEEE Spectrum
• A magnetic field, with magnitude greater than the switching field, sets magnetization in direction of applied field Summary
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
Writing a Bit
• MRAM Utilizes a Wire Directly Over & Magnetically Coupled to the Magnetic Element • A Current Pulse Traveling Down the Wire Creates a Magnetic Field Parallel to the Wire • Each Cell is Inductively Coupled with a Write Wire From a Row & a Column Diagram Courtesy:
IBM
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
Hybrid Ferromagnet Semiconductor Structures
• A Ferromagnetic Element is Placed Directly Over a Semiconducting Channel • The Fringe Field has a Large Component Perpendicular to the Plane of the Channel Diagram Courtesy:
IEEE Spectrum
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
Magnetic Tunnel Junctions
• 2 Ferromagnetic Films Separated by a Dielectric Tunnel Barrier • Resistance Between Films Depends on their Magnetic States • Parallel Fields: Low Resistance • Antiparallel Fields: High Resistance Diagram Courtesy:
IEEE Spectrum
Comparison
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals • Hybrid Ferromagnet Semiconductor: – Problems with Cross-Talk Between Cells – Compatable with Standard CMOS Processing • Magnetic Tunnel Junction – Fabrication Requirements Cause Problems with Operating Margins and Yields – Not Compatable with Standard CMOS Processing • All-Metal Spin Valve – Low Impedance, Low Readout Voltage – Not Compatable with Standard CMOS Processing Market Summary
Current Challenges
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
• • • • •
Interference Manufacturing Uniformity Power efficiency Size
Interference
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary -Interference between adjacent cells -Disturbance by digit line current to adjacent line current -The effect of heat cause bit flip
Manufacturing
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary • As chips get smaller the individual circuits hold less of the charge • Risks of leaking current and other problems • Hard to integrate with other silicon-based chips • The resistance of the magnet device varies exponentially with it thickness
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
Uniformity
-Distribution of the electromagnetic field
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
Power efficiency
• High Current consumption – MRAM designs required a relatively high current to write each single bit • Power consumption is significantly greater than DRAM, only 99% of the total power is used in delivering electric current for writing data • One transistor is required for each memory bit
The Players
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary • Principal Players: • Additional Players: – – – –
Bosch Intel Toshiba - Hewlett-Packard - NVE Corporation Siemens - Sony
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
Impacts on Broader Society
• Engineers / Scientists – Designing MRAM – Designing Hardware/Software that Interacts with MRAM – New Memory Standards • Society – Added Convenience • Longer Battery Life on Portable Electronics • “Instant-On” Computing – Higher Productivity • Data not Lost in Power Failure • Faster Read & Write
Market impacts
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
• Huge demand of memory
– MRAM is expected to be the standard memory
• The market size was $21 billion in 1999 when DRAM came out • $48 billion in 2001 • $72 billion within 2007 with MRAM
Market analysis
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
• IBM being the leader in the development of MRAM is chase by: • Motorola • Intel • Siemens • Toshiba
Next 5 years
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
• IBM and Infineon are planning the mass production for 2004 • MRAM will become the standard memory for the next couple of year • MRAM will be use in other devices
I&O long term
Overview Introduction Historical Perspective Technical Description Challenges / Constraints • Digital camera • Cellular phones • PDA • Palm pilot • MP3 • HDTV Principals Market Summary
Quality of life impacts
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary • MRAM will eliminate the boot up time • Electronic devices will be more power efficient • It could enable wireless video in cell phones • More accurate speech recognition • MP3, instead of hundred on songs, MRAM will enable thousand of songs and movies
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
Summary
• Importance – Potentially Substantial Impact on Society – Potentially Central to Computers and Electronics that Engineers are Designing • The Future of MRAM – Expected to Replace SRAM, DRAM, & FLASH – Predicted to be the Memory Standard in both Computers & Consumer Electronics • Indicators of a Breakthrough – Price of MRAM is Equivalent to or Only Slightly More than DRAM & FLASH – MRAM is More Common in New PCs than DRAM & More Common in New Electronics than FLASH
Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary
References
• Bonsor, Kevin. How Magnetic RAM Will Work. 9 Feb 2003.
• Daughton, James. Magnetoresistive Random Access Memory (MRAM). 4 Feb 2000. 1-13. 13 Feb 2003.
• Goodwins, Rupert. Magnetic Memory Set to Charge the Market. ZDNet UK. 12 Feb 2003. 16 Feb 2003.
• Guth, M., Schmerber, G., Dinia, A. “Magnetic Tunnel Junctions for Magnetic Random Access Memory Applications.”
Materials Science and Engineering.
Online 2 Jan 2002: 19. Science Direct. 16 Feb 2003.
• Johnson, Mark. “Magnetoelectronic memories last and last.”
IEEE Spectrum
37 (2000 Feb): 33-40.