Patent
MRAM synthetic antiferromagnet structure
| العنوان: | MRAM synthetic antiferromagnet structure |
|---|---|
| Patent Number: | 8,497,538 |
| تاريخ النشر: | July 30, 2013 |
| Appl. No: | 11/444089 |
| Application Filed: | May 31, 2006 |
| مستخلص: | An MRAM bit (10) includes a free magnetic region (15), a fixed magnetic region (17) comprising an antiferromagnetic material, and a tunneling barrier (16) comprising a dielectric layer positioned between the free magnetic region (15) and the fixed magnetic region (17). The MRAM bit (10) avoids a pinning layer by comprising a fixed magnetic region exhibiting a well-defined high Hflop using a combination of high Hk (uniaxial anisotropy), high Hsat (saturation field), and ideal soft magnetic properties exhibiting well-defined easy and hard axes. |
| Inventors: | Pietambaram, Srinivas V. (Chandler, AZ, US); Akerman, Bengt J. (Spånga, SE); Dave, Renu W. (Chandler, AZ, US); Janesky, Jason A. (Gilbert, AZ, US); Rizzo, Nicholas D. (Gilbert, AZ, US); Slaughter, Jon M. (Tempe, AZ, US) |
| Assignees: | Everspin Technologies, Inc. (Chandler, AZ, US) |
| Claim: | 1. An MRAM bit comprising: a free magnetic region; an electrode; a fixed magnetic region consisting of a synthetic antiferromagnetic material grown on the electrode, with H flop greater than the switching field of the free magnetic region and with broken magnetic symmetry to define a preferred set direction of the magnetic moments of the synthetic antiferromagnet; and a tunneling barrier comprising a dielectric layer positioned between the free magnetic region and the fixed magnetic region, the fixed magnetic region comprising: a first ferromagnetic layer; a second ferromagnetic layer; a first anti-ferromagnetic coupling spacer layer grown between the first and second ferromagnetic layer; a third ferromagnetic layer grown between the first ferromagnetic layer and the first anti-ferromagnetic coupling spacer layer; and wherein the first ferromagnetic layer and the second ferromagnetic layer comprise an amorphous cobalt-iron-boron alloy, the third ferromagnetic layer comprises one of a crystalline cobalt-iron alloy and a crystalline cobalt-iron-boron alloy, and the first anti-ferromagnetic coupling spacer layer comprises at least one of the elements Ruthenium, Rhodium, Chromium, Vanadium, Molybdenum, combinations and alloys thereof. |
| Claim: | 2. The MRAM bit of claim 1 wherein the third ferromagnetic layer comprises a thickness less than a thickness of the first ferromagnetic layer. |
| Claim: | 3. An MRAM bit comprising: a free magnetic region; an electrode; a fixed magnetic region consisting of a synthetic antiferromagnetic material grown on the electrode, with H flop greater than the switching field of the free magnetic region and with broken magnetic symmetry to define a preferred set direction of the magnetic moments of the synthetic antiferromagnet; and a tunneling barrier comprising a dielectric layer positioned between the free magnetic region and the fixed magnetic region, the fixed magnetic region comprising: a first ferromagnetic layer; a second ferromagnetic layer; a first anti-ferromagnetic coupling spacer layer grown between the first and second ferromagnetic layer; a third ferromagnetic layer; and a second anti-ferromagnetic coupling spacer layer grown between the second and third ferromagnetic layers, wherein the thickness of the second ferromagnetic layer is twice that of each of the first and third ferromagnetic layers. |
| Claim: | 4. The MRAM bit of claim 3 wherein the second anti-ferromagnetic coupling spacer layer comprises at least one of Ruthenium, Rhodium, Chromium, Vanadium, Molybdenum, combinations thereof, and alloys thereof. |
| Current U.S. Class: | 257/296 |
| Patent References Cited: | 5372698 December 1994 Liao 5583725 December 1996 Coffey 6545906 April 2003 Savtchenko 7151653 December 2006 Mauri et al. 7221545 May 2007 Gill 7242047 July 2007 Mori et al. 7369429 May 2008 Tanizaki 2004/0264069 December 2004 Freitag et al. 2005/0047198 March 2005 Engel et al. 2007/0183187 August 2007 Guo |
| Primary Examiner: | Armand, Marc |
| Attorney, Agent or Firm: | Ingrassia Fisher & Lorenz, P.C. |
| رقم الانضمام: | edspgr.08497538 |
| قاعدة البيانات: | USPTO Patent Grants |
| الوصف غير متاح. |