1. Magnetic RAM: The Universal Memory

2. Overview Introduction Historical perspective Technical Description Challenges Principals Market impacts Summary Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

3. Introduction 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

4. 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 Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

5. Historical Overview Why MRAM Became an Important Research Topic –Universal Memory (Computing & Electronics) –“Instant-On” Computing –Read & Write to Memory Faster –Reduced Power Consumption –Save Data in Case of a Power Failure Modern MRAM Technology Emerged from Several Technologies : –Magnetic Core Memory –Magnetoresistive RAM –Giant Magnetoresistance Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

6. Magnetic Core Memory 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 Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

7. Giant Magnetoresistance Materials Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary 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

8. Technical Overview Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary 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

9. Basic Principles Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary 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

10. Writing a Bit Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary 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

11. Hybrid Ferromagnet Semiconductor Structures Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary 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

12. Magnetic Tunnel Junctions Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary 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

13. Comparison Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary 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

14. Current Challenges Interference Manufacturing Uniformity Power efficiency Size Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

15. Interference -Interference between adjacent cells -Disturbance by digit line current to adjacent line current -The effect of heat cause bit flip Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

16. Manufacturing 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

17. Uniformity -Distribution of the electromagnetic field Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

18. 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 Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

19. The Players Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary Principal Players: Additional Players: –Bosch- Hewlett-Packard –Intel- NVE Corporation –Siemens - Sony –Toshiba

20. Impacts on Broader Society Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary 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

21. Market impacts 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 Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

22. Market analysis IBM being the leader in the development of MRAM is chase by: Motorola Intel Siemens Toshiba Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

23. Next 5 years 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 Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

24. I&O long term Digital camera Cellular phones PDA Palm pilot MP3 HDTV Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

25. Quality of life impacts 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

26. 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 Summary Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary

27. 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.. IBM Magnetic RAM Images. 16 Feb 2003.. Johnson, Mark. “Magnetoelectronic memories last and last.” IEEE Spectrum 37 (2000 Feb): 33-40. References Overview Introduction Historical Perspective Technical Description Challenges / Constraints Principals Market Summary