Multilayer structure for reducing film roughness in magnetic devices
US9780299B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 23, 2015 |
| Grant date | Oct 3, 2017 |
| Priority date | — |
| Expiry date | Nov 23, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F10/3254
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A seed layer stack with a smooth top surface having a peak to peak roughness of 0.5 nm is formed by sputter depositing an amorphous layer on a seed layer such as Mg where the seed layer has a resputtering rate 2 to 30× that of the amorphous layer. The uppermost seed layer is a template layer that is NiCr or NiFeCr. As a result, perpendicular magnetic anisotropy in an overlying magnetic layer that is a reference layer, free layer, or dipole layer is substantially maintained during high temperature processing up to 400° C. and is advantageous for magnetic tunnel junctions in embedded MRAMs, spintronic devices, or in read head sensors. The amorphous seed layer is SiN, TaN, or CoFeM where M is B or another element with a content that makes CoFeM amorphous as deposited. The seed layer stack may include a bottommost Ta or TaN buffer layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.