Magnetic tunnel junction for MRAM applications
US9455400B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 28, 2015 |
| Grant date | Sep 27, 2016 |
| Priority date | — |
| Expiry date | Dec 28, 2035 |
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 layer for improved bit switching performance. According to one embodiment, the amorphous layer has a NiFeM1/NiFeM2 configuration where M1 and M2 are Mg, Hf, Zr, Nb, or Ta, and M1 is unequal to M2. The crystalline layer is Fe, Ni, or FeB with a thickness of at least 6 Angstroms that affords a high magnetoresistive ratio. The M1 and M2 elements in the NiFeM1 and NiFeM2 layers each have a content of 5 to 30 atomic %. The NiFeM1/NiFeM2 configuration substantially reduces bit line switching current and number of shorted bits. In an alternative embodiment, the crystalline layer may be a Fe/NiFe bilayer. 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.