Multilayer structure for reducing film roughness in magnetic devices
US12356865B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 17, 2018 |
| Grant date | Jul 8, 2025 |
| Priority date | — |
| Expiry date | Oct 31, 2039 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F10/3254
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A seed layer stack with a uniform top surface having a peak to peak roughness of 0.5 nm is formed by sputter depositing an amorphous layer on a smoothing layer such as Mg where the latter has a resputtering rate 2 to 30× that of the amorphous layer. The uppermost seed layer is NiW, NiMo, or one or more of NiCr, NiFeCr, and Hf while the bottommost seed layer is one or more of Ta, TaN, Zr, ZrN, Nb, NbN, Mo, MON, TIN, W, WN, and Ru. Accordingly, perpendicular magnetic anisotropy in an overlying magnetic 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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.