Underlayer for high performance magnetic tunneling junction MRAM
US7611912B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 30, 2004 |
| Grant date | Nov 3, 2009 |
| Priority date | — |
| Expiry date | Jun 30, 2024 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/1114
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An MRAM structure is disclosed in which the bottom electrode has an amorphous TaN capping layer to consistently provide smooth and dense growth for AFM, pinned, tunnel barrier, and free layers in an overlying MTJ. Unlike a conventional Ta capping layer, TaN is oxidation resistant and has high resistivity to avoid shunting of a sense current caused by redeposition of the capping layer on the sidewalls of the tunnel barrier layer. Alternatively, the α-TaN layer is the seed layer in the MTJ. Furthermore, the seed layer may be a composite layer comprised of a NiCr, NiFe, or NiFeCr layer on the α-TaN layer. An α-TaN capping layer or seed layer can also be used in a TMR read head. An MTJ formed on an α-TaN capping layer has a high MR ratio, high Vb, and a RA similar to results obtained from MTJs based on an optimized Ta capping layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.