Magnetic tunnel junction for MRAM applications
US8786036B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 19, 2011 |
| Grant date | Jul 22, 2014 |
| Priority date | — |
| Expiry date | Nov 13, 2031 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10N50/80
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A MTJ in an MRAM array is disclosed with a composite free layer having a lower crystalline layer contacting a tunnel barrier and an upper amorphous NiFeX layer for improved bit switching performance. The crystalline layer is Fe, Ni, or FEB with a thickness of at least 6 Angstroms which affords a high magnetoresistive ratio. The X element in the NiFeX layer is Mg, Hf, Zr, Nb, or Ta with a content of 5 to 30 atomic % NiFeX thickness is preferably between 20 to 40 Angstroms to substantially reduce bit line switching current and number of shorted bits. In an alternative embodiments, the crystalline layer may be a Fe/NiFe bilayer. Optionally, the amorphous layer may have a NiFeM1/NiFeM2 configuration where M1 and M2 are Mg, Hf, Zr, Nb, or Ta, and M1 is unequal to M2. Annealing at 300° C. to 360° C. provides a high magnetoresistive ratio of about 150%.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.